Year	%
2000	17.6
2001	17.3
2002	17.1
2003	17
2004	16.8
2005	16.6
2006	16.3
2007	16
2008	15.7
2009	15.5
2010	15.2
2011	15
2012	14.8
2013	14.5
2014	14.3
2015	14.3
2016	14.2
2017	14.1
2018	13.9
2019	13.9