Year	%
2000	31.3
2001	30.8
2002	30.3
2003	30.1
2004	29.9
2005	29.9
2006	30.1
2007	30.5
2008	30.6
2009	30.8
2010	31.1
2011	30.9
2012	30.9
2013	30.7
2014	30.7
2015	30.6
2016	30.3
2017	30.2
2018	30.1
2019	29.9