Year	%
2000	14.3
2001	13.7
2002	13.8
2003	14.6
2004	14.9
2005	15.3
2006	16.4
2007	16.8
2008	16.9
2009	17.1
2010	16.7
2011	17.2
2012	18.2
2013	19.3
2014	20.8
2015	21.5
2016	21.7
2017	21
2018	20
2019	19.1