Year	Number of
1990	2836
1991	4750
1992	7025
1993	9325
1994	11440
1995	12950
1996	13680
1997	14730
1998	15720
1999	16480
2000	17260
2001	17270
2002	17740
2003	17860
2004	18000
2005	17750
2006	17090
2007	16400