Year	Number of
1980	26100
1981	25650
1982	24710
1983	24220
1984	24360
1985	24060
1986	22950
1987	22140
1988	20740
1989	20180
1990	16460
1991	16710
1992	18140
1993	19960
1994	20620
1995	21460
1996	23410
1997	28340
1998	27760
1999	32880
2000	32940
2001	36780
2002	40180
2003	37040
2004	38400
2005	39610
2006	41260
2007	37520