Year	Number
1971	27974
1972	32896
1973	41437
1974	49360
1975	75634
1976	81890
1978	83139
1979	80590
1980	76709
1981	74539
1982	74803
1983	74359
1984	74979
1985	76268
1987	77004
1988	75892
1989	79035
1992	79882
1993	79611
1994	91103
1995	100369
1996	106338
1997	117033
1998	125287
2000	150041
2001	181655
2004	232292
2005	252488
2006	269287
2010	278890