Year	Number
1970	107100
1971	137500
1972	144000
1973	77500
1974	81000
1975	85000
1976	89000
1977	110000
1978	110000
1979	145000
1980	115000
1981	97000
1982	100000
1983	95000
1984	85000
1985	90000
1986	80900
1987	85000
1988	86500
1989	109500
1990	129600
1991	129600
1992	159200
1993	34000
1994	43800
1995	48200
1996	51300
1997	51300
1998	51100
1999	58700
2000	61031