Year	%
2000	25.5
2001	25.1
2002	25
2003	25.3
2004	25.1
2005	25
2006	24.3
2007	23.7
2008	23.4
2009	23.1
2010	22.6
2011	22.1
2012	21.7
2013	21.3
2014	21.1
2015	21.1
2016	21
2017	20.9
2018	20.6
2019	20.4