What Percent of UK Internet Users Buy Online?

The number of internet users in UK is seen to grow steadily over the next few years from 37 million to 42 million. However, a larger percent of them will shop online as is seen in this projection of the percent of internet shoppers (among Internet users in UK) over the next few years:

2009 : 72.5%
2010 : 72.9%
2011 : 73.7%
2012 : 74.8%
2013 : 75.7%