The UK SME + Public Sector Email Marketing Benchmark Report 2014

This report is the result of an analysis of over 1.5 billion email messages sent through the Sign-Up.to online marketing platform in the 12 months from 1st January - 31st December 2013. These email campaigns are all from small-medium sized UK organisations across 25 sectors and public sector organisation. All of these messages were permission-based and sent to opted-in lists.

Overall averages
Across all industries the average results for UK SME email marketing campaigns were:
• Open rate: 21.47%
• Click-through rate: 3.16%
• Unsubscription rate: 0.47%
• Click-to-open rate: 14.72%
• Unsubscribe-to-open rate: 2.29%

Source: http://blog.signupto.com/