Year	% of total
1960	91.0689812699863
1961	89.39914163090128
1962	90.19917176099389
1963	90.91527730520585
1964	89.92816091954023
1965	91.5892809763863
1966	92.47653230259525
1967	86.84308609765189
1968	87.64008965738073
1969	76.68962949171477
1970	76.56408522150828
1971	80.33412887828162
1972	83.58487853960041
1973	81.70750500847589
1974	77.63896687254352
1975	74.40160358448296
1976	77.96321887955779
1977	78.16192136354832
1978	79.24633896091781
1979	77.1516393442623
1980	85.62049120531734
1981	83.62825492734859
1982	83.22953159465422
1983	83.87821953882715
1984	82.99155609167673
1985	81.18261069052537
1986	80.40719976394216
1987	76.90309298563795
1988	74.50922509225093
1989	70.38711643974803
1990	60.02695692236812
1991	58.042715068799644
1992	57.611231852654385
1993	68.39635848851138
1994	61.477299548767796
1995	63.297361489060634
1996	55.48814818642141
1997	67.75625529049634
1998	75.64886428113846
1999	69.41940873811808
2000	75.65989898989899
2001	53.18484681225502
2002	44.76243228432754
2003	55.89352941176471
2004	53.050585885486015
2005	49.36600846877141
2006	49.52282090699462
2007	46.55236678922241
2008	48.90108925549916
2009	50.53965982914727
2010	48.006908396946564
2011	50.131369475720454
2012	46.033875523751234
2013	46.23525352848928
2014	54.748572351719375
2015	49.61932197388803
2016	49.1007475636861