Year	% of total
1992	9.988384470882906
1993	10.043201492537314
1994	51.05949367088608
1995	49.18350148367952
1996	40.783341288782815
1997	20.775347467608952
1998	20.03899628252788
1999	20.287015209125475
2000	23.684351254480287
2001	23.611642441860464
2002	21.306881868131867
2003	19.198694481830415
2004	21.879531149646755
2005	19.340431300061617
2006	18.52950865438303
2007	18.771778718898886
2008	19.765765895953756
2009	21.371539582321514
2010	21.41429462571977
2011	18.62848357203033
2012	18.719066484517306
2013	18.343391304347826
2014	21.016105695228323
2015	21.710285568587455
2016	21.667144136078782