Year	Number
1961	58.611111111111114
1962	74.72222222222223
1963	84.86486486486487
1964	108.64864864864865
1965	108.10810810810811
1966	118.42105263157893
1967	131.57894736842107
1968	138.1578947368421
1969	141.02564102564102
1970	146.92307692307693
1971	149
1972	154.75
1973	156.58536585365854
1974	162.19512195121953
1975	163.8095238095238
1976	169.04761904761904
1977	170.69767441860466
1978	176.046511627907
1979	181.3953488372093
1980	178.44444444444446
1981	179.34782608695653
1982	183.69565217391303
1983	189.1304347826087
1984	194.1304347826087
1985	218.60465116279067