Year	%
2000	26.3
2001	25.9
2002	25.8
2003	25.6
2004	25.3
2005	24.9
2006	24.5
2007	23.9
2008	23.3
2009	22.6
2010	21.9
2011	21.3
2012	20.8
2013	20.3
2014	19.9
2015	19.6
2016	19.4
2017	19.3
2018	19.2
2019	19.1