Year	%
2000	24.3
2001	24.6
2002	25.1
2003	25
2004	24.3
2005	24.2
2006	22.4
2007	21.1
2008	21
2009	20.2
2010	19.9
2011	18.6
2012	17.7
2013	17
2014	18.1
2015	16.7
2016	17.1
2017	16.1
2018	16
2019	15.2