Year	%
2000	16
2001	15.6
2002	15.3
2003	15.1
2004	14.9
2005	14.8
2006	14.8
2007	14.7
2008	14.6
2009	14.6
2010	14.5
2011	14.6
2012	14.7
2013	14.7
2014	14.9
2015	15.1
2016	15.4
2017	15.7
2018	15.9
2019	16.2