Year	%
2000	27.4
2001	26.8
2002	26.8
2003	26.9
2004	26.8
2005	27.2
2006	27.9
2007	27.8
2008	27
2009	26
2010	24.9
2011	23
2012	21.9
2013	21.3
2014	21
2015	20.7
2016	20.6
2017	21.1
2018	21.2
2019	21.2