Year	%
2000	38.4
2001	37.8
2002	37.2
2003	36.6
2004	36
2005	35.4
2006	34.9
2007	34.2
2008	33.4
2009	32.8
2010	32.2
2011	31.8
2012	31.5
2013	31.2
2014	31.1
2015	30.9
2016	30.8
2017	30.6
2018	30.4
2019	30.2