Year	Number of
1980	2702
1982	13920
1983	13680
1984	13130
1985	13830
1986	12920
1987	11210
1988	11320
1989	11040
1990	11610
1991	11330
1992	11430
1993	13340
1994	13340
1995	13510
1996	15330
1997	16520
1998	15320
1999	16650
2000	18570
2001	18250
2002	18930
2003	19730
2004	19810
2005	21340
2006	21140
2007	21370