Year	Number of
1980	9163
1981	9682
1982	8697
1983	8817
1984	8544
1985	8717
1986	9427
1987	9794
1988	10130
1989	10630
1990	9414
1992	9370
1993	9774
1994	14890
1995	9866
1996	11920
1997	13350
1998	14560
1999	15080
2000	15750
2001	17390
2002	20590
2003	20700
2004	20290
2005	21510
2006	23900
2007	19780