Year	Annual Number
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	18010
1978	0
1979	0
1980	0
1981	0
1982	0
1983	164600
1984	0
1985	3000
1986	7500
1987	0
1988	90040
1989	0
1990	11000
1991	0
1992	9127
1993	572000
1994	38610
1995	33180
1996	10870
1997	35000
1998	0
1999	0
2000	677
2001	0
2002	35000
2003	600
2004	0
2005	0
2006	1502
2007	18000
2008	20000