Year	%
2000	55.2
2001	55.2
2002	55.3
2003	55.3
2004	55.2
2005	55.1
2006	54.9
2007	54.7
2008	54.3
2009	54
2010	53.5
2011	53
2012	52.5
2013	52
2014	51.4
2015	50.8
2016	50
2017	49
2018	48.1
2019	47.2