Year	years
1998	7
1999	7
2000	7
2001	8
2002	8
2003	7.5
2004	8.5
2005	8
2006	9
2007	9
2008	8
2009	8
2010	8
2011	8
2012	8
2013	8
2014	8
2015	8
2016	8
2017	8
2018	8
2019	8
2020	8
2021	8
2022	8
2023	8