Year	Number
1973	52089
1974	49433
1975	44556
1976	46630
1978	42787
1979	42348
1981	42101
1982	42378
1983	43874
1984	40315
1985	43009
1986	42453
1987	40602
1988	44515
1989	45336
1990	46540
1991	48345
1992	48175
1993	46050
1994	46560
1995	44272
1996	37962
1997	38277
1998	35164
1999	31096
2000	28978
2001	27315
2002	25805
2003	26677
2009	742
2011	6212
2012	3980
2013	2938
2014	3671
2015	4053
2016	2670