Year	%
2000	27.2
2001	26.7
2002	26.2
2003	25.7
2004	25.5
2005	25.2
2006	24.9
2007	24.5
2008	24.1
2009	23.8
2010	23.7
2011	23.5
2012	23.4
2013	23.2
2014	23
2015	22.8
2016	22.7
2017	22.6
2018	22.6
2019	22.5