Year	%
1983	3.2
1987	4.1
1990	3.2
1993	2.7
1999	3.7
2004	3.2
2005	3.5
2006	3.5
2007	3.5
2008	3.4
2009	3.6
2010	3.6
2011	3.6
2012	3.7
2013	3.5
2014	3.5
2015	3.5
2016	3.5
2017	3.5
2018	3.5
2019	3.4
2020	3.6
2021	3.6