Do you have a source for those numbers? Seem pretty inflated when you look at documented sales, shipments, and any relevance on casual observance.
Here's the source article at NPD though, which CNET cited.
https://www.npd.com/wps/portal/npd/us/news/pressreleases/pr_120502
Big market, apparently, in pre-paid. Lot of people don't want to pay ~100/month for a smart phone on AT&T/Verizon/Sprint/TMO.
24%+15%+10%+7%, thats 56% that are certainly Android based, between Samsung/HTC/Moto/LG. That 10% Other category is likely at least half Android, with some Bada, WinMo/WP7, and BREW mixed in.