Year	%
2000	26.4
2001	26.1
2002	25.9
2003	25.7
2004	25.5
2005	25
2006	24.4
2007	23.9
2008	23.4
2009	22.9
2010	22.4
2011	22
2012	21.6
2013	21.4
2014	21.2
2015	20.9
2016	20.7
2017	20.6
2018	20.5
2019	20.6