Year	Number
1990	24
1991	25
1992	26
1993	27
1994	27
1995	26
1996	26
1997	26
1998	26
1999	26
2000	25
2001	25
2002	24
2003	23
2004	22
2005	22
2006	20
2007	20
2008	20
2009	20
2010	20
2011	19
2012	19
2013	18
2014	19
2015	19
2016	19
2017	19
2018	19
2019	19
2020	19
2021	18
2022	17