Year	%
2000	17.6
2001	17
2002	16.7
2003	16.2
2004	15.8
2005	15.2
2006	14.7
2007	14.7
2008	14.2
2009	13.8
2010	13.2
2011	12.9
2012	12.7
2013	12.4
2014	12.3
2015	12
2016	12.2
2017	11.9
2018	11.5
2019	11.2