Most Popular US Amateur Radio Call Sign Prefixes

I was playing around with the FCC database of amateur radio call signs, and decided to do something fun, yet interesting. I counted a list of all of the prefixes for every amateur radio call sign currently in use. This list has active call signs filtered, and is the data from August 14, 2013. This list makes no attempt to find out if any of these people are actually active. The main purpose of this list is to help identify difficult prefixes, for use in the CQ WPX award. In addition, this list could could be used to help one find an empty prefix for a cool looking Vanity Call Sign, but that's not quite the intent. There are a total of 884 US prefixes in use right now, pretty amazing actually.