Thinking about using the internet, which of the following have you used in the last 6 months? Read blogs / weblog:
March 2008 50.7%
March 2009 41.3%
July 2010 40.8%
16-54 year old active internet users in the UK, Wave 5 Social Media Tracker from Universal McCann
The small decline between 2009 and 2010 is (probably, as different sources vary in their measures and dates) counter-balanced by the increase in the absolute number of people using the internet in the UK. Even so, if the decline continues it will at some point eat into absolute numbers as well.