Year	% of total
1960	100
1961	100
1962	100
1963	100
1964	98.18181818181819
1965	97.23502304147465
1966	95.31772575250837
1967	96.70329670329672
1968	95.45454545454545
1969	95.42168674698796
1970	94.98861047835989
1971	93.58974358974359
1972	93.4873949579832
1973	94.26086956521739
1974	92.67734553775743
1975	94.91833030852995
1976	94.6788990825688
1977	94.59459459459458
1978	95.55895865237368
1979	95.3674121405751
1980	95.82689335394127
1981	95.30685920577618
1982	95.69471624266144
1983	94.13333333333334
1984	96.4622641509434
1985	98.39449541284404
1986	98.54166666666666
1987	98.54166666666666
1988	98.63281250000001
1989	98.61660079051384
1990	98.62965517241379
1991	99.1179207920792
1992	98.99093596059114
1993	98.86519607843137
1994	98.86519607843137
1995	98.79538834951455
1996	98.90322115384615
1997	99.00899999999999
1998	99.00899999999999
1999	98.93981132075471
2000	146.43222972972973
2001	153.19375
2002	136.20285714285714
2003	121.93520325203254
2004	109.21856115107913
2005	92.00047337278107
2006	111.44803921568626
2007	122.23333333333332
2008	130.10315068493153
2009	135.55255172413794
2010	136.1426436781609
2011	90.07656410256409
2012	90.02184426229508
2013	88.71257641921397
2014	81.95189393939395
2015	59.60541818181818
2016	71.59380952380953