Year	%
1998	12.6
1999	12.6
2000	12.9
2001	13
2002	13.1
2003	13.5
2004	14
2005	13.8
2006	13.5
2007	13.2
2008	13.6
2009	13.8
2010	13.4
2011	13.9
2012	14
2013	14
2014	14
2015	14.3
2016	14.4
2017	14.2