Year	%
2000	52.4
2001	53.6
2002	53.9
2003	53.5
2004	52.4
2005	51.8
2006	50.6
2007	49.5
2008	49.1
2009	50.3
2010	50.7
2011	49.9
2012	48.2
2013	47.3
2014	46.6
2015	46.2
2016	45.8
2017	45.3
2018	45.1
2019	44.8