Year	%
2000	54.9
2001	54.8
2002	54.7
2003	54.5
2004	54.3
2005	54
2006	53.7
2007	53.3
2008	52.8
2009	52.3
2010	51.8
2011	51.2
2012	50.6
2013	50
2014	49.3
2015	48.6
2016	47.8
2017	47
2018	46.2
2019	45.3