Year	%
2000	28.2
2001	28.1
2002	28.1
2003	28
2004	27.8
2005	27.6
2006	27.5
2007	27.3
2008	27.1
2009	27
2010	26.8
2011	26.8
2012	26.7
2013	26.6
2014	26.5
2015	26.3
2016	26.2
2017	26
2018	25.8
2019	25.7