Year	Number
1960	1366
1961	1366
1962	1366
1963	1366
1964	1366
1965	600
1966	600
1967	600
1968	600
1969	600
1970	1200
1971	1200
1972	1200
1973	1200
1974	1200
1975	2300
1976	2300
1977	2500
1978	2700
1979	2800
1980	3300
1981	3340
1982	4034
1983	4666
1984	4905
1985	5168
1986	5444
1987	6561
1988	8171
1989	9213
1990	10381
1991	11298
1992	11763
1993	11000
1994	10000
1995	6900
1996	10254
1997	11621
1998	10825
1999	12651
2000	17568
2001	21500
2002	25105
2003	25565
2004	22972
2005	23601
2006	23362
2007	23123
2008	16770
2009	33451
2010	39664
2011	38901
2012	44363
2013	45338
2014	49612
2015	16983
2016	13403
2017	12333
2018	12960
2019	11393
2020	11671
2021	11893
2022	10327