Year	Number
1961	306264
1962	336793
1963	367276
1964	395262
1965	420094
1966	443845
1967	463486
1968	486738
1969	521256
1970	542678
1971	563623
1972	579438
1973	610597
1974	624962
1975	717175
1976	741053
1977	780155
1978	838472
1979	906098
1980	963011
1981	1061669
1982	1082983
1983	1113426
1984	1144150
1985	1197790.57
1986	1261176.1400000001
1987	1319535.71
1988	1380840
1989	1416593
1990	1454663
1991	1482882
1992	1487598
1993	1492246
1994	1501872
1995	1506640
1996	1498017
1997	1490641
1998	1459311
1999	1451515
2000	1444131