Year	Number
1965	2700
1966	2700
1967	2700
1968	2700
1969	2700
1970	2700
1971	2700
1972	2700
1973	2700
1974	2700
1975	2700
1976	2700
1977	2700
1978	2700
1980	11450
1981	11500
1982	12050
1983	12690
1984	14650
1985	12690
1986	15100
1987	12650
1988	12650
1989	12860
1990	13280
1991	13560
1992	13839
1993	14470
1994	15754
1995	16627
1996	17189
1997	17382
1998	17407
1999	18230
2000	18980
2001	22745
2002	24000
2003	25300
2004	26500
2005	27800
2006	29000
2007	30300
2008	31500
2009	32800
2010	14000
2011	16000
2012	18000
2013	16000
2014	16500
2015	17000
2016	17000
2017	17000
2018	4352
2019	476
2020	189
2021	269