The value of a coin depends upon its rarity, which usually depends on the mintage (number of coins minted), shown in the plot. Exceptions exist: the 1927-D Double Eagle gold piece had a mintage of 180,000, but only 14 survived. Rare mint marks "O" (New Orleans, 1909 dime and quarter) and "W" (West Point, 1996 dime) are not included here. Prior to 1980, except for 1942-1945 nickels, the Philadelphia mint did not use the "P" mintmark. After 1974, all coins produced by the San Francisco mint ("S") have only been for proof sets. The "D" coins are from the Denver mint.
Some coin-collecting notes: The easiest set to collect at the moment is the 50 State quarters (1999-2008). The Jefferson nickels are surprisingly collectible; a recent look at $50 in nickels yielded 39P, 40P, 41D, 43S, 43P, 46D, 48D, 52P, 53P, 53S, 54P, and 54S. Half dollars were silver until 1970, so rolls frequently contain silver half dollars, easily recognizable by their edge. Pre-1982 pennies are solid copper, and are worth about 2 cents each. Other coins are harder to collect; wheat cents (pre-1959 pennies), silver dimes, and silver quarters (pre-1965) are extremely rare in 2007 pocket change. The year 1909, the start of Lincoln cents, was arbitrarily chosen as the starting year.