Year	%
2000	25.5
2001	24.9
2002	24.4
2003	23.9
2004	23.3
2005	22.8
2006	22.3
2007	21.8
2008	21.3
2009	20.8
2010	20.3
2011	20
2012	19.7
2013	19.5
2014	19.3
2015	19.2
2016	19.2
2017	19.2
2018	19.3
2019	19.4