Year	Number
1970	571544
1971	602869
1972	648413
1973	703063
1974	757425
1975	788864
1976	837659
1977	846200
1978	850956
1979	855222
1980	816600
1981	838304
1982	831481
1983	851809
1984	979133
1985	1084531
1986	1087214
1987	1127096
1988	1162863
1998	518357