Year	%
2000	38.5
2001	38.4
2002	38.1
2003	38.1
2004	38.3
2005	38.5
2006	38.5
2007	38.4
2008	38.5
2009	38.6
2010	38.6
2011	38.8
2012	38.9
2013	38.9
2014	39.1
2015	39.5
2016	39.4
2017	39.5
2018	39.8
2019	39.9