Year	%
2000	23.4
2001	22.8
2002	22.2
2003	21.3
2004	20.7
2005	20.5
2006	20.6
2007	20.2
2008	19.3
2009	18.9
2010	18.8
2011	18
2012	17.4
2013	16.9
2014	16.6
2015	16.4
2016	16.3
2017	16.7
2018	17
2019	17