tedster - 6:26 am on Feb 5, 2010 (gmt 0)
I read an article within the last 3-4 weeks that I remember saying the percentage just over 40%. but I can't find the article now and I don't trust my memory all that much. What I particularly don't remember is 40% of what, exactly? All live domains? or all live pages? or all indexed pages (or domains).
However, while searching for the article, I did find this from May 2008:
We put the Alexa global top 500 websites under the microscope and found that 161 out of these 500 websites are using Google Analytics, which is 32.2%.