The source for this data are as follows:
1) The World population figures and growth are from the US Census office. The data was last updated on 23/12/2008 when 3 million people were added as a correction to the normal growth rate which is 4 people every second.
2) Phone growth were orginally derived from the GSMA web-site but they have subsequently removed that documentation so up to Oct 2009 we used Morgan Stanley internet trends reports by Mary Meecher. The latest report in Nov 2008 is here.
But the latest figure in Oct 2009 came from Tomi Ahonen's blog.
3) Phone Internet data connection is a little harder to get data for. In May 2009 we changed to using a figure of 546M connections at the end of 2008 - source is IDC 2008 data. The growth rate of Mobile Internet is even harder because many include SMS data growth which should not be included. In any case growth rates are huge but also variable from country to country depend on data plans being available or not. For example Neilsen online reports
25% growth per quarter in UK. For now we double the growth in phones to give the growth in Mobile Internet usage, but this approximation will be adjusted in future.
4) Internet growth comes from AMD 50 by 15 site..
5) Techcrunch said Steve Jobs had said at WWDC 1st Sept2010 there were now 6.5 billion downloads - we made a small upward adjustment and continued to use the calculated value of 140 downloads per second since the Sept 2009 announement of 2B downloads.