Year	%
2000	27.4
2001	26.1
2002	25.2
2003	24.5
2004	23.8
2005	23.2
2006	22.6
2007	22.1
2008	21.6
2009	20.9
2010	20.1
2011	19.5
2012	18.8
2013	18.3
2014	18.1
2015	18.1
2016	17.8
2017	17.5
2018	17.4
2019	17.4