Year	Number of
1990	26
1991	25
1992	25
1993	26
1994	26
1995	26
1996	25
1997	23
1998	22
1999	20
2000	19
2001	19
2002	19
2003	20
2004	20
2005	21
2006	21
2007	21
2008	21
2009	20
2010	20
2011	20
2012	20
2013	19
2014	18
2015	17