Year	%
2000	20.2
2001	19.8
2002	19.5
2003	19.3
2004	19.2
2005	19.1
2006	19
2007	18.9
2008	18.9
2009	18.8
2010	18.8
2011	18.8
2012	19
2013	19.1
2014	19.4
2015	19.6
2016	19.8
2017	20
2018	20.2
2019	20.3