Year	Number
1970	1500
1971	1500
1972	1500
1973	1500
1974	1500
1975	2400
1976	2600
1977	4000
1978	4000
1979	4000
1980	4000
1981	6670
1982	7180
1983	7488
1984	7797
1985	7950
1986	9582
1987	11556
1988	12804
1989	14493.5
1990	16183
1991	17844
1992	19784
1993	21873
1994	26328
1995	30043
1996	34055
1997	36258
1998	41218
1999	47338
2000	53217
2001	58036
2002	61908
2003	66639
2004	85225
2005	91191
2006	94758
2007	116746
2008	148157
2009	152461
2010	143963
2011	141529
2012	141358
2013	137421
2014	124595
2015	75075
2016	75727
2017	76000
2018	76760
2019	75291
2020	75039
2021	81374