Year	Number
1961	7
1962	8
1963	8
1964	8
1965	8
1966	10
1967	20
1968	40
1969	60
1970	98
1971	101
1972	100
1973	100
1974	100
1975	100
1976	98
1977	98
1978	98
1979	98
1980	98
1981	98
1982	95
1983	95
1984	95
1985	95
1986	95
1987	95
1988	95
1989	93
1990	93
1991	93
1992	93
1993	93
1994	90
1995	90
1996	90
1997	90