Year	%
2000	40
2001	41.3
2002	41.3
2003	40
2004	40.4
2005	41.6
2006	41.5
2007	41.4
2008	39.6
2009	37.8
2010	37.5
2011	36.3
2012	35.1
2013	34.3
2014	34
2015	31.9
2016	32.1
2017	32.5
2018	31.8
2019	31.2