"But does it have a 'P' or a 'D'???"
In 1999, the US Mint introduced the 50 State Quarters program to (and we quote) "celebrate our 50 states." Each year, five new state quarters are introduced. Since this program inception, mom has been training us to look twice before spending coinage which is certainly paying off. Her collection is almost complete! And after just 10 years of work, it will be worth $25.
