Year	%
2000	34.4
2001	33.7
2002	32.5
2003	32.2
2004	31.8
2005	31.3
2006	31.2
2007	30.8
2008	30
2009	29.8
2010	28.4
2011	27.5
2012	27.5
2013	27
2014	25.8
2015	26.5
2016	25.4
2017	24.6
2018	23.5
2019	22.8