Year	Number of
1990	4185
1991	6176
1992	8546
1993	11500
1994	14960
1995	18860
1996	22820
1997	27360
1998	32240
1999	37550
2000	43360
2001	49160
2002	54660
2003	58920
2004	61240
2005	62050
2006	61930
2007	61680