Year	Number of
1990	5162
1991	6372
1992	8716
1993	11550
1994	14990
1995	18540
1996	22340
1997	26950
1998	31310
1999	35150
2000	37470
2001	37750
2002	38600
2003	39850
2004	39900
2005	36430
2006	33180
2007	31670