Year	Number
1960	827
1961	827
1962	827
1963	827
1964	827
1965	1900
1966	1900
1967	1900
1968	1900
1969	1900
1970	4000
1971	4000
1972	4000
1973	4000
1974	4000
1975	6800
1976	8000
1977	9000
1978	10000
1979	11000
1980	12500
1981	13200
1982	15700
1983	18000
1984	20470
1985	23800
1986	26800
1987	29200
1988	31665
1989	34125
1990	38180
1991	41231
1992	43539
1993	44943
1994	47078
1995	48655
1996	51236
1997	52297
1998	53089
1999	52272
2000	53689
2001	53350
2002	53166
2003	53518
2004	53275
2005	53389
2006	53650
2007	54099
2008	54553
2009	54320
2010	54942
2011	55000
2012	62549
2013	61793
2014	60945
2015	60693
2016	60530
2017	86631
2018	90278
2019	94000
2020	94000
2021	134094
2022	138658