Year	Annual Number
1970	243100
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	3000
1979	0
1980	0
1981	0
1982	0
1983	15010
1984	0
1985	0
1986	25010
1987	2579
1988	60030
1989	0
1990	0
1991	0
1992	0
1993	25030
1994	0
1995	0
1996	418
1997	0
1998	2500
1999	2001
2000	8012
2001	33210
2002	0
2003	18810
2004	31050
2005	30610
2006	106500
2007	166600
2008	2000