Year	Number of
1980	2662
1981	2605
1982	2705
1983	2883
1984	3101
1985	2706
1986	2627
1987	3173
1988	2740
1989	2532
1990	2938
1991	3274
1992	4179
1993	4654
1994	4756
1995	5665
1996	6636
1997	7287
1998	7960
1999	8647
2000	9292
2001	9618
2002	10200
2003	9862
2004	10130
2005	10060
2006	8413
2007	7622