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
1993	732
1994	765
1995	1200
1999	2905
2000	3000
2001	13200
2002	17137
2003	18619
2004	20474