The Office for National Statistics tracks many things, and Internet take-up has been one of those for a number of years. The results for December 2008 that have just been published are also to be the last.
Broadband has well and truely done away with dial-up Internet usage, with under 5% of connections in the UK being via dial-up now, compared to around 70% in December 2005. The statistics also track the number of total connections in the UK, and the peak appears to have been in the first quarter of 2008, with the number of connections dropping slightly, from an index of 119.6 at its peak to 117.7 in December 2008. The base line was March 2005 when index was set to a baseline of 100.
The drop probably is a reflection of the state of the economy as people reassess the need for broadband or dial-up at home, and decide to get by using a connection at work during their lunch hour, or just not bothering.
The ONS has tried to track broadband speeds, based on data from providers, but it only provides information on advertised speeds which can bear little relation to what the majority of people experience.