Year	%
2000	17.4
2001	17.9
2002	17.3
2003	17.4
2004	16.9
2005	16.7
2006	16.1
2007	16.4
2008	15.8
2009	16
2010	15.7
2011	15.5
2012	15.1
2013	14.9
2014	14.6
2015	14.1
2016	13.4
2017	12.7
2018	12.4
2019	12