Year	Number
1974	51174
1976	55213
1977	55816
1978	72651
1979	80860
1980	87680
1981	96596
1982	98562
1983	117081
1984	134278
1985	154271
1986	139422
1987	155242
1988	155061
1989	168794
1990	176694
1991	184968
1996	307417
1997	327978