Year	%
2000	18.2
2001	17.3
2002	17.1
2003	17.7
2004	18.9
2005	18.4
2006	18.8
2007	19
2008	18.5
2009	19.5
2010	19.7
2011	18.6
2012	18.2
2013	18
2014	17.8
2015	18.5
2016	18.8
2017	19
2018	18.7
2019	18.6