Year	Number
1961	181.25
1962	187.5
1963	193.75
1964	199.375
1965	218.75
1966	231.25
1967	237.5
1968	250
1969	256.25
1970	259.375
1971	262.5
1972	265.625
1973	268.75
1974	271.875
1975	275
1976	281.25
1977	287.5
1978	293.75
1979	300
1980	306.25
1981	312.5
1982	318.75
1983	325
1984	331.25
1985	337.5
1986	343.75
1987	350
1988	356.25
1989	360.625