Year	Number
1965	580
1966	580
1967	580
1968	580
1969	580
1970	1560
1971	1560
1972	1560
1973	1560
1974	1560
1975	4673
1976	5454
1977	5993
1978	7113
1979	8337
1980	9559
1981	10103
1982	10721
1983	11060
1984	11770
1985	12325
1986	13300
1987	14729
1988	15757
1989	16561
1990	16605
1991	16770
1992	16860
1993	17555
1994	18475
1995	19599
1996	21116
1997	23361
1998	24968
1999	25617
2000	26180
2001	24217
2002	25330
2003	25248
2004	25128
2005	32151
2006	35983
2007	23159
2008	22818
2009	22040
2010	21822
2011	19896
2012	18910
2013	18000
2014	17200
2015	16000
2017	9267
2018	8060
2019	7133
2020	6352