Year	Number
1971	9732
1972	9543
1973	11872
1974	16382
1975	22122
1976	31871
1977	41886
1978	52525
1979	64226
1980	72986
1981	78882
1982	82307
1983	91338
1984	106221
1985	134450
1986	152206
1987	166335
1988	178571
1989	185450
1993	152321
1996	122939
1999	66725
2000	75708
2001	78284
2003	116865
2004	134946
2007	70869