Year	Number of
1980	36720
1981	39990
1982	26460
1983	28630
1984	27590
1985	30960
1986	31030
1987	30530
1988	27880
1989	26670
1990	24470
1991	25170
1992	25460
1995	22980
1996	20210
1997	25680
1998	25500
1999	22090
2000	18040
2001	17260
2002	18040
2003	17920
2004	17540
2005	19740
2006	19630
2007	18880