Year	Number of
1980	7
1981	4
1982	6
1983	2
1984	3
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	1
1992	4
1993	6
1994	2
1995	5
1996	3
1997	12
1998	5
1999	3
2000	0
2001	2
2002	3
2003	1
2004	2
2005	0
2006	1
2007	4
2008	5
2009	4
2010	2
2011	1
2012	2
2013	0
2014	7
2016	0
2017	1
2018	0
2019	2
2020	2