Year	Number
1976	12000
1977	12000
1978	12000
1979	12000
1980	15000
1981	15000
1982	65100
1983	65100
1984	113000
1985	185000
1986	195000
1987	223000
1988	227500
1989	179100
1990	242400
1991	242600
1992	239500
1993	289300
1994	297400
1995	314000
1996	373200
1997	384300
1998	368600
1999	347200
2000	393835
2001	419967
2002	518183
2003	413096
2004	461885
2005	498836
2006	545265
2007	574515
2008	586106
2009	564580
2010	412714
2011	393834
2012	235994
2013	344436
2014	407280
2015	497496
2016	567914
2017	633518
2018	455201
2019	414088
2020	149489
2021	137565