Year	% of total
1991	90.69276785714285
1992	91.97557377049182
1993	81.08718309859155
1994	79.82432926829269
1995	89.08531073446328
1996	87.85520833333334
1997	88.41751269035534
1998	88.58891089108911
1999	83.3409090909091
2000	84.11417525773196
2001	81.68764227642276
2002	82.4644600938967
2003	81.74017621145374
2004	82.27638655462185
2005	89.13853754940712
2006	85.03397637795274
2007	84.1170610687023
2008	83.74635135135135
2009	88.10481848184818
2010	90.09338658146963
2011	77.31626506024097
2012	80.69471751412429
2013	57.40486910994764
2014	82.78252499999999
2015	82.35721311475409
2016	84.61013761467889