Year	Number
1965	1400
1966	1400
1967	1400
1968	1400
1969	1400
1970	2000
1971	2000
1972	2000
1973	2000
1974	2000
1975	2700
1976	2600
1981	2000
1982	2200
1983	2430
1984	3810
1985	5310
1986	6631
1987	7107
1988	7346
1989	7666
1990	7950
1991	10236
1992	12888
1993	15550
1994	15788
1995	17255
1996	15181
1997	15867
1998	17849
1999	18993
2000	20000
2001	20543
2002	22084
2003	23895
2004	27744
2005	27800
2006	27886
2007	28500
2008	30411
2009	31121
2010	34972
2011	30010
2012	17394
2013	21253
2014	21669
2015	21774
2016	19540
2017	23409
2018	24810
2019	20936
2020	18300
2021	15976
2022	14918