Year	%
1983	13.9
1987	13.9
1990	13
1993	13.3
1999	13.5
2004	13.4
2005	13.5
2006	13.3
2007	13.4
2008	13.5
2009	13.8
2010	13.8
2011	13.8
2012	13.9
2013	13.8
2014	13.7
2015	13.9
2016	13.9
2017	13.8
2018	13.8
2019	13.7
2020	14.6
2021	14.6