Year	Number
1960	11476
1961	11476
1962	11476
1963	11476
1964	11476
1965	17600
1966	17600
1967	17600
1968	17600
1969	17600
1970	20700
1971	20700
1972	20700
1973	20700
1974	20700
1975	25400
1976	25900
1977	26500
1978	27200
1979	28200
1982	39000
1983	42274
1984	43000
1985	47512
1986	59343
1987	65580
1988	66707
1989	67016
1990	70086
1991	85947
1992	99073
1993	117337
1994	137337
1995	157843
1996	178631
1997	213516
1998	229320
1999	249083
2000	271356
2001	295234
2002	342317
2003	362976
2004	424871
2005	503930
2006	571293
2007	464090
2008	504445
2009	444265
2010	493314
2011	523865
2012	524225
2013	534810
2014	526792
2015	514920
2016	514385
2017	556112
2018	520863
2019	522605
2020	523951
2021	522141
2022	535463