Year	%
2000	46.1
2001	47.9
2002	49.4
2003	48.5
2004	47.6
2005	48.4
2006	46.9
2007	44.3
2008	44.7
2009	44.5
2010	44.8
2011	44.6
2012	40.2
2013	38.7
2014	38
2015	36.6
2016	36.5
2017	36.1
2018	36.4
2019	35.7