The United States Mint has been releasing five state quarters a year since 1999. The final five—Oklahoma, New Mexico, Arizona, Alaska, and Hawaii—will be released in 2008. Each state’s quarter is minted in two places: Denver and Philadelphia. So, for example, there is a Delaware 1999D and a Delaware 1999P. When all the quarters are released, there will be 100. I, a longtime numismatist, have 52 so far. Betcha don’t have that many. Betcha Megan doesn’t have even 10.

Addendum: Here is the folder I have.