Year	%
1970	11.1
1975	11.7
1979	12.2
1984	12.4
1990	12.6
1996	12.7
1997	12.7
1998	12.8
1999	12.5
2000	12.6
2001	12.5
2002	12.7
2003	12.8
2004	12.9
2005	13.2
2006	13.2
2007	12.7
2008	12.6
2009	12.7
2010	12.4
2011	12.5
2012	12.6
2013	12.7
2014	12.7
2015	12.8
2016	12.9
2017	13
2018	12.9
2019	13.1
2020	13.2
2021	13.1