Year	Number of
1980	2
1981	0
1982	2
1983	5
1984	0
1985	4
1986	2
1987	12
1990	0
1991	0
1992	0
1993	0
1999	17
2001	3
2002	3
2003	6
2006	7
2010	6
2011	9
2012	8
2013	2
2014	1
2015	2
2016	2
2017	4
2018	2
2019	4