Year	%
2000	18.7
2001	15.7
2002	16.6
2003	17.3
2004	16.7
2005	20.3
2006	21.4
2007	21.2
2008	20.8
2009	20.2
2010	19.5
2011	19.2
2012	14.4
2013	13.8
2014	13.5
2015	13.6
2016	12.6
2017	12.2
2018	11.8
2019	11.4