Year	Number
1990	30
1991	29
1992	28
1993	27
1994	26
1995	25
1996	24
1997	23
1998	23
1999	22
2000	21
2001	21
2002	20
2003	20
2004	20
2005	19
2006	19
2007	18
2008	17
2009	17
2010	16
2011	16
2012	16
2013	15
2014	15
2015	15
2016	14
2017	14
2018	13
2019	13
2020	12
2021	12
2022	12