Year	%
2001	18.3525947664524
2002	18.7163936079123
2003	16.4926431590032
2004	16.4275055690432
2005	17.4638524511054
2006	15.6975620673968
2007	13.4773130645656
2008	11.3069968619796
2009	15.7616683430689
2010	15.2237368881715
2011	15.5239782626475
2012	19.0334632515481
2013	20.0234515566461
2014	19.5662487907201
2015	24.0849036904366
2016	20.5139576642709
2017	22.129750984416
2018	19.5829450568144