Year	%
1979	2.7
1986	2.6
1992	2.8
1997	2.4
2001	2.3
2002	2.1
2003	1.9
2004	1.8
2005	1.8
2006	1.8
2007	1.8
2008	1.8
2009	1.6
2010	1.7
2011	1.8
2012	1.7
2013	1.8
2014	1.7
2015	1.8
2016	1.9
2017	1.8
2018	1.9
2019	1.8
2020	1.9
2021	1.9