go on windows media player and on al muic at the side, see what years you have in your mp3 collection.
Unknown,1899,1965,1966,1967,1968,1970,1971,1973,1978,1980,1984,1986,1987,1988,1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005.

31 different years of music :)