Year	Number
1960	117
1961	111
1962	105
1963	98
1964	90
1965	80
1966	71
1967	62
1968	54
1969	48
1970	42
1971	37
1972	34
1973	31
1974	28
1975	25
1976	24
1977	23
1978	22
1979	21
1980	19
1981	17
1982	15
1983	15
1984	14
1985	14
1986	14
1987	14
1988	14
1989	14
1990	14
1991	14
1992	14
1993	15
1994	15
1995	16
1996	18
1997	18
1998	17
1999	16
2000	17
2001	17
2002	16
2003	15
2004	14
2005	14
2006	13
2007	13
2008	14
2009	14
2010	13
2011	12
2012	12
2013	11
2014	10
2015	10
2016	10
2017	10
2018	9
2019	9
2020	9
2021	9
2022	9