Year	%
2000	34.7
2001	34.5
2002	34.5
2003	34.7
2004	35.6
2005	35.2
2006	35.3
2007	34.6
2008	33.4
2009	33.2
2010	32.8
2011	32.9
2012	32.6
2013	32
2014	31.7
2015	31.3
2016	31.2
2017	30.7
2018	30.8
2019	30.6