Year	%
2000	32.5
2001	31.9
2002	31.8
2003	32
2004	32.1
2005	32.1
2006	31.5
2007	30.8
2008	30.7
2009	30.3
2010	29.8
2011	29.5
2012	29.3
2013	28.7
2014	28.4
2015	28.4
2016	28.2
2017	28.2
2018	27.4
2019	27.2