Year	%
2000	46.4
2001	46.6
2002	46.1
2003	45.3
2004	44.3
2005	43.6
2006	42.6
2007	41.5
2008	40.8
2009	41.4
2010	41.6
2011	40.9
2012	38.5
2013	37.4
2014	36.5
2015	36.1
2016	35.8
2017	35.4
2018	35.2
2019	35