Year	Number
1961	72.99307327743347
1962	77.81897491821157
1963	84.16332482683194
1964	92.55822416302766
1965	101.28785114921561
1966	112.53536452665941
1967	101.39258726160489
1968	108.53986316168528
1969	117.50887973023605
1970	119.91669470929146
1971	132.08101265822785
1972	139.5143421572501
1973	144.26849100860048
1974	151.20927051060235