Year	%
2000	19.9
2001	19.7
2002	20
2003	19.4
2004	19
2005	18.7
2006	18.6
2007	19.3
2008	20.1
2009	20.1
2010	20.3
2011	20.4
2012	20.2
2013	20.2
2014	20.2
2015	20.3
2016	20.1
2017	19.3
2018	18.6
2019	18.6