Year	Number
1990	25
1991	24
1992	24
1993	23
1994	22
1995	22
1996	22
1997	22
1998	23
1999	24
2000	24
2001	24
2002	24
2003	23
2004	22
2005	21
2006	20
2007	18
2008	17
2009	15
2010	15
2011	14
2012	13
2013	12
2014	12
2015	12
2016	12
2017	12
2018	12
2019	13
2020	13
2021	14
2022	15