Total data service revenues in the US for 2006 was $15.2 billion, a 77 percent increase over the figure in 2005 ($8.6 billion) according to the CTIA Semi-Annual Wireless Industry Survey. Wireless data revenues now account for roughly 13 percent of all wireless revenues in the US. Of course, a lot of that is SMS, with more than 158 billion messages being sent in 2006, a 95 percent increase year-on-year. MMS messages more than doubled from 1.1 billion in 2005 to 2.7 billion in 2006. (release)
From the sample of the report (PDF) we find that telcos in the US added about 25 million subscriber lines in 2006, while six-month revenue rose to $65 billion from $57.8 billion in 2005. Average revenue per user seems to have stabilized after falling for most of the past decade or so. In 2006 it was $50.56, 2005—$49.98, 2004—$50.64, and in 2003 $49.91.