Year	Number
1990	15
1991	15
1992	14
1993	14
1994	15
1995	15
1996	15
1997	15
1998	15
1999	15
2000	15
2001	15
2002	15
2003	15
2004	14
2005	14
2006	12
2007	12
2008	12
2009	10
2010	10
2011	9
2012	9
2013	9
2014	9
2015	9
2016	8
2017	8
2018	8
2019	7
2020	7
2021	7
2022	7