Year	%
1992	37.8
1993	37.8
1995	45.7
1996	42.7
2002	38
2003	38
2004	37.9
2005	38
2006	38.8
2007	36.6
2008	36.4
2009	35.4
2010	35.2
2011	34.9
2012	35
2013	35.1
2014	34.6
2015	35.6
2016	35.1
2017	36
2018	36.1
2019	36.5
2020	35.9