Year	Number
1960	600
1961	600
1962	600
1963	600
1964	600
1965	3000
1966	3000
1967	3000
1968	3000
1969	3000
1970	8100
1971	8100
1972	8100
1973	8100
1974	8100
1975	12300
1976	14300
1977	17100
1978	18100
1979	22000
1980	30600
1981	41200
1982	51918
1983	60400
1984	64833
1985	69501
1986	74281
1987	77474
1988	83215
1989	88913
1990	92071
1991	96662
1992	105527
1993	110300
1994	115766
1995	122701
1996	133513
1997	141902
1998	150508
1999	154904
2000	160191
2001	167446
2002	176519
2003	184508
2004	190876
2005	205386
2006	228327
2007	237368
2008	265865
2009	287942
2010	270000
2011	309000
2012	394407
2013	412584
2014	417589
2015	459887
2016	467148
2017	461561
2018	452088
2019	461289
2020	454701
2021	460240
2022	523765