Year	Number
1970	27700
1971	31300
1972	38600
1973	63400
1974	70700
1975	72800
1976	73700
1977	71000
1978	71900
1979	75100
1980	88600
1981	97800
1982	95800
1983	95100
1984	95100
1985	94700
1986	94100
1987	101400
1988	109400
1989	111900
1990	130500
1991	145800
1992	164800
1993	164500
1994	175000
1995	178200
1996	188300
1997	194100
1998	174000
1999	164800
2000	169263
2001	169840
2002	189382
2003	166716
2004	170054
2005	176152
2006	163665
2007	185052
2008	176549
2009	182002
2010	302185.222466875
2011	336401
2012	343382
2013	430334.457756879
2014	443318.55
2015	463740
2016	447001
2017	473610.67
2018	474940
2019	498878
2020	167785
2021	83981.767