Year	%
2000	25
2001	24.3
2002	23.4
2003	23.2
2004	22.9
2005	22.5
2006	22.4
2007	22.2
2008	21.6
2009	21.5
2010	20.6
2011	20
2012	20.1
2013	19.7
2014	19
2015	19.4
2016	18.6
2017	18.2
2018	17.4
2019	17