How Many iPhones & iPads Are Jailbroken?

Now that 3GS iPhone are being sold for $50 and the used unlocked iPhone market is huge. How big is the market and how many phones are jailbroken?  This is the largest category on eBay unlocked iPhones.  We think that greater than 10% of iPhones have been jailbroken  and possibly 20-30 million iPhones unlocked?  We were not surprised to see that Apple supporters quickly tried to bury the link in Google.  Here is a story on how to jailbreak the iPhone 4 for T-Mobile and think this is one of the major reasons why AT&T is acquiring T-Mobile to prevent this massive defection that is going unpublicized.  If anyone has any credible sources of information we would appreciate a post in the comments section below.