Year	%
2000	33
2001	32.6
2002	32.5
2003	32.6
2004	32.7
2005	32.5
2006	32
2007	32
2008	32.3
2009	32.2
2010	31.7
2011	31.7
2012	31.6
2013	31.4
2014	31.4
2015	31.2
2016	30.9
2017	30.8
2018	30.7
2019	30.4