Year	%
2000	59
2001	58.9
2002	58.8
2003	58.6
2004	58.5
2005	58.3
2006	58
2007	57.8
2008	57.5
2009	57.1
2010	56.8
2011	56.5
2012	56.1
2013	55.8
2014	55.4
2015	55
2016	54.6
2017	54.1
2018	53.6
2019	53