Year	% of total
1990	63.47571828121027
1991	63.97404910316754
1992	66.71984915512364
1993	79.32419453418318
1994	89.58508443493544
1995	77.82989149457474
1996	77.9134083539958
1997	76.54182709135456
1998	79.83139301485348
1999	85.90024761230987
2000	85.89511754068717
2001	85.90766078876125
2002	85.90840463009563
2003	85.90685400470723
2004	85.87940030381085
2005	85.87737559599759
2006	85.87757350409694
2007	85.87997302764666
2008	85.87666468742047
2009	92.18623116484707
2010	91.80165289256198
2011	93.27747723974139
2012	93.479694092827
2013	93.47655413603597
2014	91.2572055997804
2015	85.1880276285495