Year	%
2000	58.8
2001	58.7
2002	58.6
2003	58.5
2004	58.4
2005	58.2
2006	58
2007	57.9
2008	57.7
2009	57.5
2010	57.3
2011	57.1
2012	56.9
2013	56.8
2014	56.6
2015	56.3
2016	56.1
2017	55.9
2018	55.6
2019	55.3