CTIA - the wireless association - states that there are 95% of wireless subscribers as of 31st December 2011.In Dec. 2010, there were 311 million wireless subscriber connection which increased to 331 million in Dec. 2011. The data traffic of wireless network which was 331 billion in Dec. 2010 increased to 866.7 billion within a year.
There were 13.6 million wireless enabled mobiles, laptops and tablets in 2010 December which increased by 6.6 million in Dec. 2011. The Minutes of Use (MOU) also increased from 2.241 trillion to 2.296 trillion in the same period. CTIA also reports that there was a 12% increase in SMS sent and received from the year 2010.
You can also find information on total service revenues, subscriber to employee ratio, incremental capital investment, etc in the CTIA Report indices.