Year	%
2000	31.1
2001	30.7
2002	30.4
2003	29.9
2004	30
2005	29.3
2006	29.1
2007	29.2
2008	29.2
2009	29.4
2010	29.1
2011	28.7
2012	28.1
2013	28.3
2014	27.5
2015	26.1
2016	26.2
2017	26
2018	25.5
2019	24.9