Year	%
2000	31.2
2001	30.6
2002	30.9
2003	32
2004	31.5
2005	31.1
2006	30.4
2007	29.5
2008	29.2
2009	28.1
2010	26.7
2011	25.7
2012	25.8
2013	25.1
2014	25.1
2015	26.1
2016	26.8
2017	26.4
2018	26.4
2019	26.7