Year	%
2000	21.8
2001	20.7
2002	22.2
2003	21.3
2004	20.9
2005	19
2006	19.6
2007	23.8
2008	24.1
2009	21.5
2010	20
2011	19.3
2012	18.6
2013	18.8
2014	19
2015	18.8
2016	17.6
2017	17.3
2018	17.6
2019	17.5