Year	Number
1961	381412
1962	413450
1963	445320
1964	476556
1965	504271
1966	529661
1967	550727
1968	575368.52
1969	611887.12
1970	635386.72
1971	658675.08
1972	675815.08
1973	712069.88
1974	725150.04
1975	823517.48
1976	851035.32
1977	893575.32
1978	918590
1979	986764
1980	1043294
1981	1143015
1982	1164524
1983	1194951
1984	1225922
1985	1280145.57
1986	1347784.1400000001
1987	1408868.71
1988	1465797
1989	1500125
1990	1535917
1991	1565880
1992	1573242
1993	1580110
1994	1589756
1995	1596799
1996	1589672
1997	1592951
1998	1562983