Year	years
1998	6
1999	6
2000	6
2001	6
2002	6
2003	6
2004	6
2005	6
2006	6
2007	6
2008	6
2009	6
2010	6
2011	6
2012	6
2013	6
2014	6.5
2015	6.5
2016	6.5
2017	6.5
2018	6.5
2019	6.5
2020	6.5
2021	6.5
2022	6.5
2023	6.5