Year	%
2000	25.4
2001	24.9
2002	24
2003	24.2
2004	22.7
2005	21.7
2006	21.3
2007	20.6
2008	18.9
2009	19.2
2010	18
2011	17.6
2012	16.9
2013	17.3
2014	16.2
2015	16.5
2016	16
2017	15.6
2018	15.4
2019	14.8