Year	Number
1965	9500
1966	9500
1967	9500
1968	9500
1969	9500
1970	12500
1971	12500
1972	12500
1973	12500
1974	12500
1975	12500
1976	15100
1977	15100
1978	15100
1979	18500
1980	19100
1981	19300
1982	19441
1983	19645
1984	21137
1985	22226
1986	23457
1987	25000
1988	25500
1989	27750
1990	31543
1991	36306
1992	36583
1993	34806
1994	33675
1995	37074
1996	39406
1997	43197
1998	47193
1999	50226
2000	54995
2001	58399
2002	59491
2003	59598
2004	58702
2005	92366
2006	129809
2007	133894
2008	164851
2009	186150
2010	142065
2011	138322
2012	143227
2013	145772
2014	148555
2015	148635
2016	148585
2017	68792
2018	69046
2019	73673
2020	49645
2021	26271
2022	25761