Year	%
2000	18.8
2001	18.4
2002	18.1
2003	17.9
2004	17.7
2005	17.5
2006	17.3
2007	17.2
2008	17
2009	16.9
2010	16.8
2011	16.8
2012	16.8
2013	16.8
2014	16.9
2015	17
2016	17.1
2017	17.2
2018	17.4
2019	17.5