Year	% of total
1990	79.91454722452374
1991	78.4383767961742
1992	76.71395220286749
1993	74.02082039793908
1994	75.2813713657312
1995	72.61735204749192
1996	74.68188877374003
1997	71.51172881564104
1998	65.62115215413807
1999	65.13010634443096
2000	62.59379319599059
2001	60.81016615058027
2002	64.33873431699722
2003	66.82846998694264
2004	67.4902820746596
2005	69.13749757916409
2006	70.07984629185805
2007	65.9402086122655
2008	74.03490808227251
2009	68.296833373664
2010	72.05739476917084
2011	73.8792778054359
2012	73.52748127404728
2013	70.21484563962379
2014	69.1214454653616
2015	68.86287021416027
2016	66.53673227911767