Year	Number of
1986	3
1987	3
1988	3
1989	3
1990	3
1991	3
1992	3
1993	3
1994	3
1995	3
1996	2
1997	2
1998	2
1999	1
2000	1
2001	1
2002	1
2003	1
2004	1
2005	1
2006	1
2007	1
2008	1
2009	1
2010	1
2011	1
2012	1
2013	1
2014	1
2015	1