Year	Number of
1990	4467
1991	6955
1992	10550
1993	15390
1994	21360
1995	28220
1996	35820
1997	44660
1998	55800
1999	70600
2000	89360
2001	110100
2002	129300
2003	144200
2004	154500
2005	161200
2006	165300
2007	167800