Year Number of 1990 485500 1991 497500 1992 508400 1993 518700 1994 529000 1995 539600 1996 551700 1997 565500 1998 572000 1999 592800 2000 596000 2001 598500 2002 563500 2003 541300 2004 516800 2005 457500 2006 418500 2007 364800