Year	Number
1961	31134
1962	34003
1963	35269
1964	37590
1965	40166
1966	43588
1967	47895
1968	51996
1969	56768
1970	61237
1971	60692
1972	55708
1973	53050
1974	53768
1975	55587
1976	56423
1977	57338
1978	55864
1979	56352
1980	58108
1981	57268
1982	57402
1983	57401
1984	58827
1985	58726
1986	59180
1987	59695
1988	55926
1989	57359
1990	57437
1991	56255
1992	58614
1993	62049
1994	65380
1995	63996
1996	63652
1997	68853
1998	74650