Year	% of total
1990	92.83863165169316
1991	92.50319829424308
1992	91.16024895005819
1993	87.26576032754187
1994	89.59080302771612
1995	90.87068763201125
1996	90.9990050915901
1997	89.83131385127109
1998	89.15990665629514
1999	91.7143485915493
2000	91.79635274613615
2001	93.1418028465999
2002	89.19843858617186
2003	88.40082683453913
2004	87.32983811626195
2005	86.84417628541448
2006	89.74045552703419
2007	89.17929235135259
2008	89.68719678417965
2009	87.75704897180411
2010	81.5766969535008
2011	86.81383660195131
2012	92.07847572646598
2013	93.0418771944849
2014	94.0189259139437
2015	92.59154244977317