Year	%
2000	37.7
2001	37.5
2002	37.4
2003	37.3
2004	37.1
2005	37.1
2006	37.1
2007	36.9
2008	36.7
2009	36.6
2010	36.5
2011	36.3
2012	36.4
2013	36.4
2014	36.5
2015	36.6
2016	36.5
2017	36.4
2018	36.4
2019	36.3