Year	%
2000	25.4
2001	24.9
2002	24.5
2003	24.2
2004	23.8
2005	23.4
2006	22.7
2007	22.3
2008	22.1
2009	22.2
2010	22.2
2011	22.4
2012	22.6
2013	22.9
2014	23.1
2015	23.2
2016	23.3
2017	23.5
2018	23.6
2019	23.7