Year	%
2000	37.1
2001	36.7
2002	36.3
2003	36
2004	35.7
2005	35.4
2006	35.1
2007	34.8
2008	34.5
2009	34.2
2010	34
2011	33.8
2012	33.6
2013	33.5
2014	33.5
2015	33.4
2016	33.3
2017	33.3
2018	33.2
2019	33.1