Year	%
2000	56.6
2001	56.5
2002	56.4
2003	56.3
2004	56.1
2005	55.9
2006	55.8
2007	55.5
2008	55.3
2009	55
2010	54.7
2011	54.4
2012	54.2
2013	53.9
2014	53.7
2015	53.4
2016	53.2
2017	52.9
2018	52.6
2019	52.3