Year Number of 1990 23040 1991 25050 1992 25900 1993 26580 1994 27030 1995 27700 1996 28290 1997 30600 1998 32000 1999 33900 2000 36180 2001 39140 2002 39920 2003 38690 2004 39710 2005 37990 2006 36610 2007 36090