Year	Number
1970	25600
1971	27300
1972	26600
1973	26900
1974	28800
1975	29700
1976	29500
1977	28400
1978	29000
1979	30800
1980	32600
1981	34100
1982	36800
1983	40000
1984	44200
1985	47400
1986	49600
1987	48300
1988	54600
1989	61800
1990	69500
1991	69800
1992	72700
1993	76200
1994	80700
1995	86500
1996	91700
1997	94900
1998	93500
1999	95400
2000	101591
2001	102414
2002	97750
2003	93576
2004	128178
2005	124347
2006	126845
2007	129703
2008	125907
2009	123541
2010	201306
2011	227322
2012	252368.898405228
2013	298450
2014	338053.981662592
2015	392664
2016	413880
2017	448477
2018	475886.496
2019	483580
2020	224142.333
2021	119077