Year	%
2000	18.9
2001	18.2
2002	19.1
2003	18.6
2004	18.3
2005	17.4
2006	17.6
2007	20.1
2008	19.8
2009	18.5
2010	17.9
2011	17.6
2012	16.8
2013	17.3
2014	18
2015	18.1
2016	17.7
2017	17.8
2018	17.7
2019	17.5