Year	Number
1971	399700
1972	399560
1973	403700
1974	399894
1975	402219
1976	404818
1977	406432
1978	410402
1979	414624
1980	418247
1981	419998
1982	420871
1983	421539
1984	420444
1985	420665
1986	420236
1987	422150
1988	423402
1989	423662
1990	422396
1991	416747
1992	408567
1993	402226
1994	391998
1995	380983
1996	367689
1997	358830
1998	465186
1999	456564
2000	449638
2001	443617
2002	445947
2003	447618
2004	450413
2005	454060
2006	461588
2007	475836
2008	486921
2009	498838
2010	506400
2011	511466
2012	518223
2013	527768
2014	536471
2015	544856
2016	553585
2017	559151
2018	564304
2019	568495
2020	570381
2021	557157