Year	Number
1971	13568
1972	15227
1973	16459
1974	16275
1975	14091
1976	8087
1977	6577
1978	9597
1979	17107
1980	22357
1981	14339
1982	12425
1983	12623
1984	14012
1985	13700
1986	17055
1987	13721
1988	12578
1989	15637
1990	19756
1991	21136
1992	22383
1993	24252
1996	21671
1997	21096
1999	3541
2000	2722
2001	3425
2002	7997
2003	5708
2004	4603
2005	8265
2007	3884
2008	2486
2009	2089
2010	1567