Year	%
2000	30.5
2001	29.7
2002	28.9
2003	28.1
2004	27.5
2005	26.8
2006	26.4
2007	26
2008	25.6
2009	25.2
2010	24.9
2011	24.5
2012	24.2
2013	23.8
2014	23.6
2015	23.5
2016	23.4
2017	23.2
2018	23.3
2019	23.4