Year	%
2000	33.2
2001	32.9
2002	32.6
2003	32.5
2004	32.2
2005	31.9
2006	31.8
2007	31.6
2008	31.5
2009	31.3
2010	31.2
2011	31.3
2012	31.5
2013	31.7
2014	32
2015	32.3
2016	32.7
2017	33.1
2018	33.4
2019	33.7