Year	Number
1975	7100
1976	7700
1977	8600
1978	9100
1979	10200
1980	11400
1981	12800
1982	14290
1983	16496
1984	18592
1985	20691
1986	26000
1987	30404
1988	38000
1989	45457
1990	57320
1991	64894
1992	68886
1993	72683
1994	75637
1995	83713
1996	112645
1997	139989
1998	208387
1999	253035
2000	266890
2001	298062
2002	327673
2003	371816
2004	417944
2005	484640
2006	611544
2007	701126
2008	805061
2009	812615
2010	841698
2011	845542
2012	831703
2013	829097
2014	837266
2015	846940
2016	858237
2017	861299
2018	799368
2019	762000
2020	726000
2021	726000