Year	% of total
1964	71.22950819672131
1965	65.33052039381153
1966	82.59551243177683
1967	78.89273356401385
1968	77.71395749569213
1969	76.96903856599674
1970	80.32345013477088
1971	80.20134228187919
1972	76.59384752563531
1973	77.4792572105887
1974	75.10121457489879
1975	70.60379021595415
1976	82.32118758434548
1977	79.17981072555204
1978	79.48717948717949
1979	81.9557625145518
1980	80.09893455098934
1981	76.52545666537117
1982	80.27465667915106
1983	79.74062390466176
1984	78.30746489283075
1985	78.49231868524473
1986	82.7094972067039
1987	85.37054860442733
1988	83.30676383511728
1989	84.16402356139557
1990	81.23747126436783
1991	69.85334426229508
1992	73.22087709799675
1993	73.57616510538641
1994	84.98892857142857
1995	68.60227390180879
1996	70.69956258411844
1997	68.69990600144614
1998	69.22211798152097
1999	67.05835018963337
2000	73.95562773722628
2001	68.69689208633093
2002	73.10512409927942
2003	80.47227897838899
2004	76.00486182190379
2005	80.7019124643197
2006	83.33751780264495
2007	80.0653381147541
2008	78.45450000000001
2009	46.227858064516134
2010	57.52816513761467
2011	50.99970409051349
2012	28.403352601156072
2013	57.17078478964402
2014	63.682057613168716
2015	64.85266935483871
2016	64.33099181073703