Year	Number
1960	0
1965	0
1970	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	867
1992	1301
1993	1907
1994	4098
1995	4965
1996	5803
1997	5673
1998	12837
1999	20000
2000	27200
2001	32600
2002	70500
2003	79800
2004	98000