Year	%
1994	39
1995	38.2
1996	38
1997	37.6
1998	39.7
1999	38.3
2000	37.7
2003	38.1
2004	38.5
2005	37.5
2006	38.3
2007	38.7
2008	38.6
2009	39.3
2010	38.4
2011	38.7
2012	38.4
2013	38.9
2014	38.7
2015	38.4
2016	38.6
2017	37.8
2018	38.7
2019	38.2
2020	37.8
2021	38.5