Year	Number of
1980	29990
1981	27080
1982	25400
1983	22980
1984	20240
1985	20070
1986	17910
1987	17100
1988	16280
1989	15380
1990	14650
1991	13470
1992	14110
1993	14160
1994	12980
1995	12200
1996	11810
1997	11160
1998	10440
1999	9974
2000	9064
2001	6959
2002	6931
2003	6526
2004	6007
2005	5539
2006	5021
2007	4609