Year	%
2000	19.2
2001	18.8
2002	18
2003	18.1
2004	18.1
2005	18.4
2006	18.8
2007	19
2008	19.4
2009	20
2010	20.2
2011	20.8
2012	21.1
2013	21.3
2014	21.5
2015	21.5
2016	21.3
2017	21.4
2018	21.5
2019	21.5