Year	%
2000	40.1
2001	39.3
2002	37.8
2003	36.6
2004	35.6
2005	35
2006	34.2
2007	33.3
2008	32.3
2009	32.2
2010	32.3
2011	31.7
2012	28.8
2013	27.6
2014	26.5
2015	26.1
2016	26
2017	25.8
2018	25.7
2019	25.7