Year	%
1997	33.5
1998	33.5
1999	37
2000	36.5
2001	36.5
2002	36.5
2003	37.5
2004	37.5
2005	37.5
2006	38
2007	41.5
2008	41.5
2009	40
2010	40
2011	42.5
2012	42.5
2013	42.5
2014	42.5
2015	41.5
2016	41.5
2017	42
2018	42
2019	47
2020	46
2021	46
2022	45.5
2023	46