Year	%
2000	20.2
2001	19.2
2002	18.1
2003	17.8
2004	17.1
2005	16.6
2006	16.3
2007	15.9
2008	15.7
2009	16.1
2010	16.2
2011	15.8
2012	15.2
2013	15.2
2014	14.8
2015	14.7
2016	14.2
2017	13.7
2018	13.8
2019	12.9