Year	Number
1961	211
1962	269
1963	314
1964	402
1965	400
1966	450
1967	500
1968	525
1969	550
1970	573
1971	596
1972	619
1973	642
1974	665
1975	688
1976	710
1977	734
1978	757
1979	780
1980	803
1981	825
1982	845
1983	870
1984	893
1985	940