Search Engine Land had an interesting summary of reports out that shows that according to Gene Munster of Piper Jaffray believes that Android generates about $5.90 as of right now, but will increase to $9.85 in 2012. In 2010 Google generated $850 million in mobile ads, $130 of which was from Android (hence the $5.90 figure). This is the answer to the question many have asked about how does Google make money off of Android. It is no surprise that Android has been growing at faster and faster rates. Looking to the future, the same analyst believes that Google could average 133 Million Android users by 2012. IDC shared information that shows that more smartphones were shipped in Q4 of 2010 than PCs. With Android's success and the ease of use for hardware manufactures the number of Android users is going to climb steadily as more and more users adopt the Android platform.
Source: Search Engine Land