Year	%
2000	35.7
2001	33.6
2002	31.8
2003	30.9
2004	30.6
2005	29.8
2006	29.3
2007	28.8
2008	28.3
2009	28.2
2010	27.6
2011	27
2012	27.1
2013	26.4
2014	25.8
2015	24.6
2016	24.2
2017	23.6
2018	23.1
2019	22.6