Year	%
2000	27.9
2001	27.7
2002	27.7
2003	27.7
2004	27.6
2005	27.5
2006	27.3
2007	26.9
2008	26.6
2009	26.3
2010	25.9
2011	25.7
2012	25.6
2013	25.5
2014	25.5
2015	25.6
2016	25.6
2017	25.7
2018	25.7
2019	25.8