Year	Number
1961	2
1962	2
1963	2
1964	2
1965	3
1966	4
1967	5
1968	6
1969	7
1970	9
1971	9
1972	9
1973	9
1974	18
1975	14
1976	20
1977	25
1978	25
1979	29
1980	25
1981	24
1982	24
1983	23
1984	23
1985	60
1986	102
1987	100
1988	96
1989	92
1990	88
1991	86
1992	84
1993	82
1994	80
1995	78
1996	76
1997	75
1998	82
1999	87
2000	89
2001	92
2002	99
2003	105
2004	105
2005	105
2006	107
2007	109
2008	109