Year	%
2000	36.2
2001	35.8
2002	35.2
2003	34.8
2004	34.7
2005	34.6
2006	33.6
2007	31.9
2008	30.7
2009	30.1
2010	29.4
2011	29.1
2012	28.4
2013	27.8
2014	26.8
2015	26.1
2016	25.9
2017	24.9
2018	24.7
2019	24.7