Year	%
2000	26.6
2001	26.4
2002	26.7
2003	26.2
2004	25.1
2005	24.5
2006	23.8
2007	24.3
2008	23.1
2009	22.9
2010	22.8
2011	22.4
2012	22.1
2013	21.6
2014	20.7
2015	20.8
2016	21
2017	20.4
2018	20.3
2019	19.7