Year	%
2000	30.6
2001	31
2002	30.9
2003	31.1
2004	31.1
2005	31.6
2006	31.7
2007	31.3
2008	30.9
2009	30.6
2010	30.1
2011	30
2012	29.9
2013	29.1
2014	28.4
2015	27.6
2016	27
2017	26.4
2018	26
2019	25.7