Year	%
2000	17.5
2001	16.9
2002	16.5
2003	16.6
2004	16.6
2005	16.4
2006	16.4
2007	16.3
2008	16.1
2009	16
2010	15.9
2011	15.7
2012	16
2013	15.4
2014	15.5
2015	15.7
2016	15.9
2017	15.7
2018	16
2019	16.1