Year	%
2000	39.7
2001	39
2002	39
2003	39.2
2004	39.4
2005	39.6
2006	39.1
2007	38.2
2008	38.3
2009	37.9
2010	37.4
2011	37.4
2012	37.2
2013	36.5
2014	36.2
2015	36.1
2016	35.9
2017	35.8
2018	34.7
2019	34.4