Year	Number of
1980	0
1981	0
1982	4
1983	0
1984	0
1985	1
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0
1995	2
1997	0
2001	0
2002	0
2003	0
2004	0
2006	0
2007	0