Year	Number of
1980	1
1981	0
1982	0
1983	1
1984	7
1985	9
1986	5
1987	13
1988	6
1989	5
1990	1
1991	1
1992	0
1994	0
1998	1
1999	2
2000	0
2001	0
2002	0
2003	1
2004	0
2005	1
2006	0
2007	2
2010	0
2011	0
2012	0
2013	0
2014	0
2015	0
2016	0
2017	0
2018	0
2019	0