Year	Number of
1980	37
1981	10
1982	19
1983	29
1984	20
1985	36
1986	17
1987	16
1988	20
1989	1
1990	0
1991	1
1992	6
1993	5
1994	4
1995	2
1996	1
1997	2
1998	0
1999	3
2000	1
2001	2
2002	1
2003	0
2004	1
2005	1
2006	1