Year	%
2000	37.7
2001	35.9
2002	35.8
2003	36.2
2004	35
2005	35.2
2006	35.6
2007	36.1
2008	36.8
2009	36.7
2010	35.9
2011	35.3
2012	34.9
2013	34.8
2014	34.5
2015	34.3
2016	34.1
2017	33.8
2018	33.6
2019	33.4