Year	%
2000	35.3
2001	35.5
2002	36
2003	36.4
2004	37.1
2005	37.8
2006	38.5
2007	39
2008	39.8
2009	40.9
2010	41.8
2011	42.3
2012	42.7
2013	42.5
2014	41.9
2015	41.1
2016	40.3
2017	39.7
2018	39.3
2019	38.8