Year	Number
1961	38
1962	40
1963	42
1964	44
1965	46
1966	48
1967	50
1968	52
1969	54
1970	56
1971	58
1972	60
1973	62
1974	64
1975	66
1976	68
1977	70
1978	72
1979	74
1980	76
1981	78
1982	80