Year	years
1998	9
1999	9
2000	9
2001	9
2002	9
2003	9
2004	9
2005	9
2006	9
2007	9
2008	10
2009	10
2010	11
2011	12
2012	13
2013	13
2014	13
2015	14
2016	14
2017	14
2018	14
2019	14
2020	14
2021	14
2022	13.5
2023	14