Year	%
2000	34.5
2001	33.6
2002	32.6
2003	32.1
2004	31.8
2005	31.2
2006	31.5
2007	31.7
2008	31.3
2009	31.5
2010	31.5
2011	30.3
2012	29.4
2013	28.5
2014	28
2015	27.7
2016	27.3
2017	26.5
2018	25.9
2019	25.5