Year	%
2000	16.2
2001	16.1
2002	15.9
2003	15.7
2004	15.5
2005	15.3
2006	15.1
2007	14.9
2008	14.6
2009	14.4
2010	14.2
2011	14
2012	13.8
2013	13.5
2014	13.4
2015	13.3
2016	13.1
2017	12.9
2018	12.9
2019	12.8