Year	%
2000	50.8
2001	50.6
2002	50.3
2003	50.3
2004	50.4
2005	50.5
2006	50.3
2007	50.1
2008	50.1
2009	50.1
2010	50.1
2011	50.2
2012	50.2
2013	50.3
2014	50.4
2015	51.1
2016	51.2
2017	51.5
2018	51.9
2019	52.1