Year	%
2000	18.1
2001	17.9
2002	17
2003	15.9
2004	15.3
2005	14.4
2006	14.2
2007	14.8
2008	15
2009	15.4
2010	15.5
2011	15.6
2012	15.8
2013	15.7
2014	17.2
2015	17.4
2016	17.3
2017	17.1
2018	17.1
2019	17.4