Year	%
2000	32.6
2001	32.2
2002	32.3
2003	32.5
2004	32.2
2005	32.3
2006	32.4
2007	32.2
2008	32.3
2009	32
2010	31.3
2011	30
2012	29.1
2013	28.5
2014	28.7
2015	28.8
2016	28.5
2017	27.8
2018	25.5
2019	24.1