Year	%
2000	32.6
2001	32.1
2002	32.3
2003	32.3
2004	31.8
2005	31.3
2006	31.2
2007	31
2008	31.3
2009	31
2010	30.8
2011	29.9
2012	29.7
2013	29.1
2014	28.7
2015	28.2
2016	27.7
2017	27.1
2018	26.7
2019	26.4