Year	%
2000	36.9
2001	36.4
2002	35.8
2003	35.2
2004	34.6
2005	34
2006	33.5
2007	32.9
2008	32.3
2009	31.8
2010	31.5
2011	31.4
2012	31.3
2013	31.3
2014	31.3
2015	31.3
2016	31.3
2017	31.4
2018	31.4
2019	31.4