Year	%
2000	24.3
2001	23.5
2002	23.9
2003	22.5
2004	22.4
2005	21
2006	20.3
2007	18.8
2008	18.5
2009	18.1
2010	19.5
2011	20.5
2012	21.5
2013	22.3
2014	22.6
2015	22.3
2016	21.9
2017	21.7
2018	20.9
2019	20.7
