Year	%
2000	20.7
2001	21
2002	21.2
2003	20.9
2004	19.6
2005	19.6
2006	19.5
2007	20.6
2008	20
2009	19.2
2010	18.3
2011	18
2012	18.2
2013	18
2014	18.7
2015	19
2016	19.3
2017	19.9
2018	20.2
2019	19.7