"In 2004," according to the Times, "12,386 items made their way into the lost-property office at New York City Transit, a modest white and gray room in Penn Station; in 2005, the office collected only 8,309 items, a drop of 33 percent from the previous year and the lowest number since 1998."
Way to go New York, holding onto our stuff! The drop could be attributed to the effectiveness of the "see something, say something" and the thievery awareness campaigns the MTA has been running. Or it could be attributed to an increasing number of people keeping the stuff they find for themselves.
As an example of this second theory the Times finds a young "waitress from Park Slope" who brags that the subway was how she got her scarf, or as the Times refers to it: "the colorful fringe of what appeared to be a boa of Muppet pelts."
Photogrpah of Lost Wallets by Don Hogan Charles for the New York Times.