Year	Number of
1980	14440
1981	13880
1982	13810
1983	13360
1984	12560
1985	12420
1986	13090
1987	13290
1988	13500
1989	13310
1990	10970
1991	10820
1992	10920
1993	10420
1994	10520
1995	11310
1996	13940
1997	16110
1998	20620
1999	24980
2000	25840
2001	26220
2002	27550
2003	26940
2004	26490
2005	25740
2006	23730
2007	24780