Year	%
2000	16.2
2001	15.9
2002	15.7
2003	15.6
2004	15.4
2005	15.3
2006	15.2
2007	15.1
2008	15
2009	15
2010	14.9
2011	15
2012	15
2013	15.2
2014	15.3
2015	15.6
2016	15.8
2017	16
2018	16.3
2019	16.5