Year	%
2000	33
2001	32.9
2002	32.7
2003	32.3
2004	31.9
2005	31.4
2006	31
2007	30.4
2008	29.8
2009	29.3
2010	28.9
2011	28.5
2012	28.2
2013	27.9
2014	27.8
2015	27.7
2016	27.7
2017	27.6
2018	27.6
2019	27.6