The table below looks at the statistics for VoIP skills in IT jobs advertised across the UK. Included is a guide to the salaries offered in IT jobs that have cited VoIP over the 3 months to 6 May 2016 with a comparison to the same period over the previous 2 years.

3 months to
6 May 2016
Same period 2015 Same period 2014
Voice Over IP (VoIP)
Rank 215 235 252
Rank change year-on-year
+20 +17
Permanent jobs citing VoIP 1621 1539 1438
As % of all permanent IT jobs located in the UK 1.58% 1.39% 1.20%
As % of the Communications & Networking category 9.19% 7.69% 6.98%
Number of salaries quoted 1391 1307 1160
Median salary £40,000 £40,000 £40,000
90% offered a salary of more than £23,500 £25,000 £24,300
10% offered a salary of more than £61,950 £60,000 £60,000
UK excluding London median salary £39,500 £37,500 £36,500
% change year-on-year
+5.33% +2.73%

The following table is for comparison with the above and provides statistics for the entire Communications & Networking category in permanent jobs advertised across the UK.

Communications & Networking Category
UK
Permanent IT job ads with a match in the
Communications & Networking category
17642 20011 20591
As % of all permanent IT jobs located in the UK 17.21% 18.11% 17.16%
Number of salaries quoted 14649 15894 16366
Median salary £45,000 £45,000 £42,500
Median salary % change year-on-year
- +5.88%
90% offered a salary of more than £26,500 £27,500 £27,000
10% offered a salary of more than £66,500 £62,500 £67,500
UK excluding London median salary £42,500 £42,500 £40,000
% change year-on-year
- +6.25%

VoIP
Jobs Demand Trend

The demand trend of job ads citing VoIP as a proportion of all IT jobs with a match in the Communications & Networking category.

VoIP Jobs Demand Trend in the UK

VoIP
Salary Trend

This chart provides the 3-month moving average for salaries quoted in permanent IT jobs citing VoIP within the UK.

VoIP Salary Trend in the UK

VoIP
Salary Histogram

This chart provides a salary histogram for IT jobs citing VoIP over the 3 months to 6 May 2016 within the UK.

VoIP Salary Histogram in the UK

VoIP
Top 30 Job Locations

The table below looks at the demand and provides a guide to the median salaries quoted in IT jobs citing VoIP within the UK over the 3 months to 6 May 2016. The 'Rank Change' column provides an indication of the change in demand within each location based on the same 3 month period last year.

Location
(Click see detailed
statistics and trends)
Rank Change
on Same Period
Last Year
Matching
Permanent
IT Job Ads
Median Salary
Last 3 Months
Median Salary
% Change
on Same Period
Last Year
Live
Job
Vacancies
England +22 1530 £40,000 - 142
London +18 589 £45,000 -2.56% 42
South East -10 350 £40,000 - 31
South West +64 140 £28,500 -18.57% 17
East of England +62 110 £41,000 +2.50% 6
West Midlands +17 107 £40,000 +10.81% 17
City of London +10 106 £45,500 -4.21% 9
Berkshire +4 94 £50,000 +21.95% 5
Yorkshire 0 94 £32,500 - 10
North West +20 79 £37,000 -1.33% 12
Surrey -40 79 £35,000 -12.50% 6
Hampshire -2 62 £40,000 +6.66% 6
Buckinghamshire +44 55 £35,000 -17.64% 6
Reading +9 54 £40,000 - 1
Manchester +3 54 £39,750 +6.00% 9
West Yorkshire -27 50 £32,500 - 6
Hertfordshire +30 41 £47,500 +14.45% 2
East Midlands -14 41 £32,500 -4.41% 5
Leeds -27 37 £35,000 +7.69% 4
North Yorkshire +19 29 £42,500 +19.71% 3
Birmingham -4 29 £29,375 -17.83%
Wales -8 28 £30,000 - 1
Watford +27 26 £45,000 +20.00%
Newbury +26 26 £62,500 +29.53%
Aylesbury +5 26 £38,000 -15.55% 1
Cornwall +10 25 £20,500 -4.65% 1
Wiltshire +6 25 £36,750 -5.76% 2
South Wales 0 25 £28,750 +4.54% 1
Redruth - 25 £20,500 - 1
Gloucestershire +13 23 £33,000 -12.00% 3

VoIP
Top 30 Related IT Skills

For the 6 months to 6 May 2016, IT jobs citing VoIP also mentioned the following skills in order of popularity. The figures indicate the number co-occurrences and its proportion to all job ads with a requirement for VoIP.

1 1519 (50.75%) Cisco
2 1214 (40.56%) Windows
3 1104 (36.89%) Firewall
4 910 (30.40%) WAN
5 893 (29.84%) Cisco Certification
6 889 (29.70%) Microsoft
7 852 (28.47%) Active Directory
8 817 (27.30%) LAN
9 773 (25.83%) VMware
10 710 (23.72%) Telecoms
11 705 (23.55%) VPN
12 661 (22.08%) ITIL
13 617 (20.61%) Windows Server
14 616 (20.58%) TCP/IP
15 603 (20.15%) CCNP
16 578 (19.31%) Linux
17 558 (18.64%) VMware Infrastructure
18 518 (17.31%) DNS
19 513 (17.14%) MS Exchange
20 510 (17.04%) CCNA
21 463 (15.47%) Wireless
22 420 (14.03%) MPLS
23 398 (13.30%) MS Excel
24 395 (13.20%) Data Centre
25 392 (13.10%) Finance
26 366 (12.23%) MS Office
27 347 (11.59%) BGP
28 346 (11.56%) Windows Server 2008
29 345 (11.53%) DHCP
30 336 (11.23%) Cisco ASA

VoIP
Top Related IT Skills by Category

The follow tables expand on the table above by listing co-occurrences grouped by category. The same job type, locality and period is covered with up to 20 co-occurrences shown in each of the following categories:

Application Platforms
1 513 (17.14%) MS Exchange
2 282 (9.42%) Exchange Server 2010
3 172 (5.75%) Skype for Business
4 148 (4.94%) Exchange Server 2013
5 123 (4.11%) Exchange Server 2007
6 110 (3.68%) SharePoint
7 79 (2.64%) IIS
8 74 (2.47%) Apache
9 51 (1.70%) Blackberry Enterprise Server
10 30 (1.00%) Tomcat
11 26 (0.87%) Confluence
12 20 (0.67%) CMS
13 18 (0.60%) nginx
14 16 (0.53%) Exchange Server 2003
14 16 (0.53%) SharePoint 2013
15 13 (0.43%) SharePoint 2010
16 12 (0.40%) OpenStack
17 7 (0.23%) Moodle
18 5 (0.17%) BizTalk Server
18 5 (0.17%) Office Communications Server
Applications
1 398 (13.30%) MS Excel
2 366 (12.23%) MS Office
3 59 (1.97%) MS Visio
4 33 (1.10%) MS PowerPoint
5 9 (0.30%) Adobe Creative Suite
6 8 (0.27%) MS Project
7 3 (0.10%) AutoCAD
8 1 (0.033%) Adobe After Effects
8 1 (0.033%) CINEMA 4D
8 1 (0.033%) Spreadsheet
Business Applications
1 45 (1.50%) Dynamics CRM
2 15 (0.50%) Cisco SocialMiner
3 9 (0.30%) Oracle Applications
3 9 (0.30%) SAP Oil and Gas
4 4 (0.13%) Unit4 Business World
5 3 (0.10%) Maximo
5 3 (0.10%) SAP CRM
6 2 (0.067%) FLEXCUBE
7 1 (0.033%) Dynamics AX
7 1 (0.033%) Payment Gateway
7 1 (0.033%) Sage 50
7 1 (0.033%) SAP SM
Cloud Services
1 222 (7.42%) Office 365
2 105 (3.51%) Microsoft Azure
3 92 (3.07%) Amazon AWS
4 72 (2.41%) SaaS
5 62 (2.07%) Cloud Computing
6 29 (0.97%) Virtual Private Cloud
7 24 (0.80%) IaaS
8 19 (0.63%) Yammer
9 12 (0.40%) Google Apps
10 10 (0.33%) Mimecast
11 7 (0.23%) PaaS
12 6 (0.20%) GitHub
13 5 (0.17%) Amazon EC2
13 5 (0.17%) Route 53
14 4 (0.13%) Azure Active Directory
14 4 (0.13%) OneDrive
15 3 (0.10%) AWS CloudFormation
16 2 (0.067%) Adobe Creative Cloud
16 2 (0.067%) Amazon CloudWatch
16 2 (0.067%) Amazon S3
Communications & Networking
1 1104 (36.89%) Firewall
2 910 (30.40%) WAN
3 817 (27.30%) LAN
4 705 (23.55%) VPN
5 616 (20.58%) TCP/IP
6 518 (17.31%) DNS
7 463 (15.47%) Wireless
8 420 (14.03%) MPLS
9 347 (11.59%) BGP
10 345 (11.53%) DHCP
11 336 (11.23%) Cisco ASA
12 332 (11.09%) Internet
13 330 (11.03%) SAN
14 328 (10.96%) OSPF
15 302 (10.09%) Unified Communications
16 275 (9.19%) Network Security
17 243 (8.12%) VLAN
18 221 (7.38%) SSL
19 214 (7.15%) EIGRP
20 203 (6.78%) PBX
Database & Business Intelligence
1 197 (6.58%) SQL Server
2 78 (2.61%) MySQL
3 47 (1.57%) SQL Server 2008
4 27 (0.90%) SQL Server 2012
5 22 (0.74%) Oracle Database
6 16 (0.53%) SQL Server 2005
7 13 (0.43%) MongoDB
8 11 (0.37%) NoSQL
9 10 (0.33%) SQL Server 2014
10 6 (0.20%) Big Data
11 5 (0.17%) Data Warehouse
11 5 (0.17%) Hadoop
11 5 (0.17%) MS Access
11 5 (0.17%) Relational Database
12 4 (0.13%) Oracle Exadata
12 4 (0.13%) Redis
12 4 (0.13%) SQLite
13 3 (0.10%) Oracle Database 11g
13 3 (0.10%) PostgreSQL
14 2 (0.067%) MariaDB
Development Applications
1 39 (1.30%) JIRA
2 29 (0.97%) Git (software)
3 14 (0.47%) InstallShield
4 13 (0.43%) Jenkins
4 13 (0.43%) Visual Studio
5 12 (0.40%) Eclipse
6 10 (0.33%) Subversion
7 9 (0.30%) Android Studio
7 9 (0.30%) TeamCity
8 8 (0.27%) Selenium
8 8 (0.27%) VSS/SourceSafe
9 7 (0.23%) Gradle
9 7 (0.23%) NeoLoad
10 4 (0.13%) ClearCase
10 4 (0.13%) CruiseControl
10 4 (0.13%) Sonatype Nexus
11 3 (0.10%) AppScan
11 3 (0.10%) Metasploit
11 3 (0.10%) Paros
12 2 (0.067%) Maven
General
1 710 (23.72%) Telecoms
2 392 (13.10%) Finance
3 118 (3.94%) Banking
4 86 (2.87%) Legal
4 86 (2.87%) Retail
5 68 (2.27%) Law
6 59 (1.97%) Marketing
7 58 (1.94%) Manufacturing
8 33 (1.10%) Games
9 28 (0.94%) Electronics
10 22 (0.74%) Billing
11 20 (0.67%) Advertising
11 20 (0.67%) Investment Banking
12 18 (0.60%) Multimedia
13 16 (0.53%) Back Office
14 9 (0.30%) Pharmaceutical
15 8 (0.27%) French Language
16 6 (0.20%) Aerospace
16 6 (0.20%) Automotive
17 5 (0.17%) Front Office
Job Titles
1 628 (20.98%) Network Engineer
2 425 (14.20%) Analyst
3 395 (13.20%) Support Engineer
4 286 (9.56%) Cisco Engineer
5 211 (7.05%) Cisco Network Engineer
6 209 (6.98%) 2nd Line Support
7 195 (6.52%) IT Support
8 194 (6.48%) IT Engineer
9 184 (6.15%) Support Analyst
10 162 (5.41%) Senior Network Engineer
11 159 (5.31%) Infrastructure Engineer
12 157 (5.25%) VoIP Engineer
13 149 (4.98%) 2nd Line Engineer
14 131 (4.38%) Voice Engineer
15 126 (4.21%) Administrator
16 118 (3.94%) Network Support
17 110 (3.68%) 2nd Line Support Engineer
18 108 (3.61%) Infrastructure Analyst
19 105 (3.51%) 3rd Line Support
20 98 (3.27%) Consultant
Libraries, Frameworks & Software Standards
1 51 (1.70%) 802.1X
2 50 (1.67%) Web Services
2 50 (1.67%) XMPP
3 41 (1.37%) LAMP
4 31 (1.04%) HTML
5 29 (0.97%) FreeSWITCH
6 27 (0.90%) .NET
7 26 (0.87%) SOAP
8 23 (0.77%) XML
9 19 (0.63%) CSS
10 18 (0.60%) LEMP Stack
11 16 (0.53%) RESTful
12 13 (0.43%) Middleware
13 9 (0.30%) Memcached
14 8 (0.27%) COM
14 8 (0.27%) Spring
14 8 (0.27%) WSH
15 7 (0.23%) .NET Framework
15 7 (0.23%) RFC 2833
16 6 (0.20%) HEVC
Miscellaneous
1 395 (13.20%) Data Centre
2 206 (6.88%) Analytical Skills
3 131 (4.38%) Video Conferencing
4 123 (4.11%) Management Information System
5 93 (3.11%) IVR
6 89 (2.97%) Computer Science
7 88 (2.94%) Blackberry
8 79 (2.64%) Driving Licence
9 68 (2.27%) iPhone
10 56 (1.87%) Handset
11 51 (1.70%) Replication
12 46 (1.54%) iPad
13 40 (1.34%) Clustering
14 37 (1.24%) Private Cloud
15 32 (1.07%) Mobile App
16 29 (0.97%) Client/Server
17 24 (0.80%) EPoS
17 24 (0.80%) User Experience
18 23 (0.77%) FMCG
18 23 (0.77%) PKI
Operating Systems
1 1214 (40.56%) Windows
2 617 (20.61%) Windows Server
3 578 (19.31%) Linux
4 346 (11.56%) Windows Server 2008
5 307 (10.26%) Windows Server 2012
6 297 (9.92%) Windows 7
7 159 (5.31%) Windows Server 2003
8 134 (4.48%) Windows 8
9 130 (4.34%) Unix
10 113 (3.78%) Android
11 100 (3.34%) Windows 10
12 86 (2.87%) Windows XP
13 52 (1.74%) Mac OS X
14 45 (1.50%) CentOS
15 39 (1.30%) Ubuntu
16 38 (1.27%) Solaris
17 33 (1.10%) Red Hat Enterprise Linux
17 33 (1.10%) Windows Vista
18 26 (0.87%) Apple iOS
19 19 (0.63%) Debian
Processes & Methodologies
1 661 (22.08%) ITIL
2 261 (8.72%) Project Management
3 208 (6.95%) Disaster Recovery
4 144 (4.81%) Service Delivery
5 131 (4.38%) Change Management
6 129 (4.31%) PRINCE2
7 127 (4.24%) Presales
8 123 (4.11%) Mentoring
8 123 (4.11%) Service Management
9 118 (3.94%) Network Design
10 113 (3.78%) Load Balancing
10 113 (3.78%) Network Management
11 112 (3.74%) Migration
12 100 (3.34%) High Availability
13 98 (3.27%) Network Monitoring
14 97 (3.24%) Capacity Planning
15 91 (3.04%) Continuous Improvement
16 88 (2.94%) CRM
17 75 (2.51%) Agile Software Development
17 75 (2.51%) Incident Management
Programming Languages
1 203 (6.78%) SQL
2 107 (3.58%) PowerShell
3 99 (3.31%) C
4 92 (3.07%) Python
5 65 (2.17%) PHP
6 57 (1.90%) Perl
7 51 (1.70%) VBScript
8 43 (1.44%) C++
9 42 (1.40%) C#
10 41 (1.37%) Bash Shell
11 37 (1.24%) Java
12 35 (1.17%) JavaScript
13 34 (1.14%) Ruby
14 17 (0.57%) VB
15 11 (0.37%) Shell Script
16 10 (0.33%) F#
17 9 (0.30%) Delphi
18 4 (0.13%) Embedded C
18 4 (0.13%) VBA
19 3 (0.10%) VB.NET
Qualifications
1 893 (29.84%) Cisco Certification
2 603 (20.15%) CCNP
3 510 (17.04%) CCNA
4 274 (9.15%) Degree
5 234 (7.82%) Microsoft Certification
6 138 (4.61%) MCSE
7 127 (4.24%) CCIE
8 93 (3.11%) Security Cleared
9 89 (2.97%) ITIL Certification
10 78 (2.61%) MCSA
11 67 (2.24%) SC Cleared
12 66 (2.21%) CCVP
13 57 (1.90%) MCP
14 54 (1.80%) CCNP Voice
15 52 (1.74%) VMware Certified Professional (VCP)
16 48 (1.60%) MCITP
17 33 (1.10%) ISEB
17 33 (1.10%) ISTQB
18 32 (1.07%) CCSA
19 31 (1.04%) CCDA
Quality Assurance & Compliance
1 299 (9.99%) SLA
2 60 (2.00%) QA
3 59 (1.97%) ISO/IEC 27001
4 41 (1.37%) PCI DSS
5 28 (0.94%) COBIT
6 25 (0.84%) Sarbanes-Oxley
7 9 (0.30%) ISO 9001
7 9 (0.30%) PA-DSS
8 7 (0.23%) JSP 440
9 1 (0.033%) HIPAA
9 1 (0.033%) HMG Security Policy Framework
9 1 (0.033%) ISO 8583
9 1 (0.033%) RMADS
9 1 (0.033%) SEPA
System Software
1 852 (28.47%) Active Directory
2 558 (18.64%) VMware Infrastructure
3 249 (8.32%) Hyper-V
4 95 (3.17%) vSphere
5 88 (2.94%) XenApp
6 61 (2.04%) Terminal Services
7 45 (1.50%) VMware Server
7 45 (1.50%) XenDesktop
8 38 (1.27%) VMware ESXi
9 35 (1.17%) Xen
10 34 (1.14%) NFS
11 30 (1.00%) XenServer
12 29 (0.97%) DFS Replication
13 17 (0.57%) Firmware
14 16 (0.53%) VMware ESX
15 14 (0.47%) KVM
15 14 (0.47%) vCloud
16 13 (0.43%) VMware Workstation
17 12 (0.40%) Docker
18 11 (0.37%) Kamailio
Systems Management
1 168 (5.61%) Cisco CUCM
2 103 (3.44%) SCCM
3 91 (3.04%) Cisco UCCX
4 76 (2.54%) Nagios
5 69 (2.31%) Cisco UCCE
6 54 (1.80%) SCOM
7 49 (1.64%) Ansible
8 38 (1.27%) Backup Exec
9 33 (1.10%) Puppet
10 25 (0.84%) Cacti
11 24 (0.80%) HP NNM
12 22 (0.74%) CiscoWorks
13 18 (0.60%) WSUS
14 17 (0.57%) FortiGate
15 15 (0.50%) Opscode Chef
16 14 (0.47%) vMotion
16 14 (0.47%) XenMobile
17 13 (0.43%) Cisco IPCC
18 12 (0.40%) Salt
19 11 (0.37%) HAProxy
Vendors
1 1519 (50.75%) Cisco
2 889 (29.70%) Microsoft
3 773 (25.83%) VMware
4 313 (10.46%) Juniper
5 307 (10.26%) Citrix
6 273 (9.12%) HP
7 260 (8.69%) CheckPoint
8 237 (7.92%) Avaya
9 194 (6.48%) F5
10 153 (5.11%) SolarWinds
11 134 (4.48%) Mitel
12 97 (3.24%) NetApp
13 87 (2.91%) Riverbed
14 78 (2.61%) Apple
14 78 (2.61%) Palo Alto
15 72 (2.41%) Red Hat
16 68 (2.27%) Veeam
17 67 (2.24%) Dell
18 51 (1.70%) Polycom
19 48 (1.60%) Oracle
Glasgow, Lanarkshire
Search Consultancy
Salary: Excellent basic salary and benefits
Posted: 5 hours ago
Manchester, Lancashire
Redrock Consulting Ltd
Posted: 5 hours ago
London
Stafford-Sharp Associates
Salary: £40000 - £50000 per annum + Bens
Posted: 5 hours ago
Abingdon, Oxfordshire
Rockfield
Salary: From £28,000 to £35,000 per annum including pension, profit share
Posted: 6 hours ago
Redruth, Cornwall
Global Technology Solutions Ltd
Salary: £20000 per annum
Posted: 6 hours ago
Basingstoke, Hampshire
ISL
Salary: £40000 - £50000 per annum + Benefits
Posted: 6 hours ago
Cambridge, Cambridgeshire
Reed Technology
Salary: £45000 - £55000 per annum + benefits
Posted: 6 hours ago
Leeds, West Yorkshire
Connected IT
Salary: £30000 - £40000 per annum + Car + Bonus + Benefits
Posted: 6 hours ago
London
Monarch Recruitment
Salary: £50000 - £80000 per annum
Posted: 6 hours ago
High Wycombe, Buckinghamshire
Monarch Recruitment
Salary: £20000 - £23000 per annum
Posted: 6 hours ago
Worcester, Worcestershire
Spring Technology
Salary: £45000.00 - £55000.00 per annum
Posted: 6 hours ago
Wolverhampton, West Midlands (County)
Spring Technology
Salary: £32000.00 - £40000.00 per annum
Posted: 6 hours ago
Richmond, Surrey
First Point
Salary: £50000.00 - £60000.00 per annum + Bonus + Benefits
Posted: 6 hours ago
City, London
Hays Finance Technology
Salary: £65000.00 - £75000.00 per annum + bonus
Posted: 6 hours ago
Stroud, Gloucestershire
TTR UK Ltd
Salary: £20000.00 per annum
Posted: 7 hours ago
Surrey
Coal IT Services
Salary: £Market Rate
Posted: 7 hours ago
City, London
Harvey Nash plc
Salary: £65000 - £75000 per annum + Bonus + Benefits
Posted: 7 hours ago
Brighton, East Sussex
Oscar
Salary: £40000 - £50000 per annum + Benefits
Posted: 7 hours ago
Swindon, Wiltshire
Robert Half
Salary: £40000 per annum
Posted: 7 hours ago
Basingstoke, Hampshire
ISL
Salary: £45000 - £50000 per annum + Benefits
Posted: 8 hours ago
London
Harris Global
Salary: From £55,000 to £60,000 per annum Benefits + Bonus
Posted: 11 hours ago
Staines, Middlesex
Greywood Associates Limited
Salary: £50000 - £51000 per annum + bens
Posted: 13 hours ago
Sidcup, Kent
Randstad Technologies
Salary: £50000.00 - £57000 per annum + great benefits
Posted: 13 hours ago
Essex
Oscar
Salary: £18000 - £23000 per annum + Benefits
Posted: 14 hours ago
City, London
Oscar
Salary: £40000 - £65000 per annum + Benefits
Posted: 14 hours ago
Manchester, Lancashire
Evolution Recruitment Solutions
Salary: 20,000 + Benefits
Posted: 22 hours ago
London
Streamline Connections
Salary: £55000 - £70000 per annum + Benefits
Posted: Yesterday
London
Oliver James Associates
Salary: £50000 - £60000 per annum + Great Benefits
Posted: Yesterday
Livingston, West Lothian
NSK International Consultants Ltd
Salary: Highly Competitive Salary + Excellent Benefits Package
Posted: Yesterday
Bristol, Avon
UWE
Salary: From £31,656 to £37,768 per annum
Posted: Yesterday
Alderley Edge, Cheshire
Chess Telecom
Posted: Yesterday
Bristol, Avon
Harvey Nash plc
Salary: £18000 - £22000 per annum + 20% Shift Allowance + Benefits
Posted: Yesterday
Bristol, Avon
Harvey Nash plc
Salary: £30000 - £37000 per annum + 20% Shift Allowance + Benefits
Posted: Yesterday
London
Think IT Recruitment
Salary: £55000 - £65000 per annum + Benefits
Posted: Yesterday
Milton Keynes, Buckinghamshire
Imperative People
Salary: £22000.00 - £25000.00 per annum + bens
Posted: Yesterday
Keighley, West Yorkshire
Connected IT
Salary: £20000 - £23000 per annum + bens
Posted: Yesterday
City, London
Capita Resourcing - IT Resourcing
Posted: Yesterday
Manchester, Lancashire
FT Select
Salary: Up to £22,000 per annum plus bonus and benefits
Posted: Yesterday
Salford, Lancashire
FT Select
Salary: Up to £40,000 per annum plus on call, bonus and excellent benefits
Posted: Yesterday
London
Harrington Starr
Salary: £25000 - £30000 per annum + bonus, benefits + training
Posted: Yesterday