Year	% of total
1960	79.6943231441048
1961	78.11676082862523
1962	78.0496092422698
1963	74.57220054037826
1964	80.17565872020074
1965	82.6735885788449
1966	71.24335106382979
1967	76.16996841803044
1968	82.23145863099104
1969	76.70596236681024
1970	73.15682281059063
1971	77.0627919045148
1972	79.59759164697813
1973	84.99696294796517
1974	84.37416777629826
1975	87.5
1976	89.46925965364568
1977	89.87621806689492
1978	85.80522565320665
1979	83.86571351008959
1980	84.96887829426566
1981	85.43581413243277
1982	84.69834994843589
1983	90.24308885460535
1984	88.46153846153845
1985	89.88824801730352
1986	88.49736879533494
1987	90.75649803895499
1988	92.86231228514565
1989	94.44314527915813
1990	94.90726096333573
1991	91.32417536300814
1992	93.69241101410343
1993	93.6518341767837
1994	93.28397018399743
1995	91.12085038378653
1996	89.38718728631723
1997	90.68881086574888
1998	91.45300996102209
1999	89.97874278773155
2000	91.93823116518483
2001	94.28178461074685
2002	93.16896839373436
2003	89.58121060357482
2004	89.70125652491797
2005	89.05211435879315
2006	87.19819206035328
2007	92.63446604264006
2008	90.8300483214649
2009	86.57151275084296
2010	81.43357679502152
2011	86.04745487730683
2012	83.19757779203897
2013	74.72773750744126
2014	75.61329281131438
2015	71.12809231600478