Year	%
1982	15.6
1992	16.5
2000	16.2
2002	16.8
2006	16.5
2007	16.4
2008	16.5
2009	16.6
2010	16.8
2011	17
2012	16.9
2013	16.6
2014	16.6
2015	16.8
2016	16.6
2017	16.7
2018	16.8
2019	16.4
2020	16.5