Year	%
2000	26.1
2001	25.3
2002	24.8
2003	23.8
2004	22.1
2005	23
2006	22.9
2007	21.8
2008	19.8
2009	19.6
2010	19.2
2011	18.1
2012	17.6
2013	17.8
2014	19
2015	19.9
2016	19.2
2017	18.5
2018	17.3
2019	17.3