Year	%
2000	46.5
2001	46
2002	45.6
2003	45.1
2004	44.6
2005	44.1
2006	43.5
2007	42.9
2008	42.2
2009	41.5
2010	40.8
2011	40.1
2012	39.4
2013	38.8
2014	38
2015	37.3
2016	36.5
2017	35.6
2018	34.7
2019	33.9