Year	%
2000	54
2001	53.9
2002	53.8
2003	53.6
2004	53.5
2005	53.2
2006	52.9
2007	52.5
2008	52.1
2009	51.6
2010	51.1
2011	50.7
2012	50.3
2013	50
2014	49.8
2015	49.6
2016	49.3
2017	48.9
2018	48.5
2019	48.1