Year	% of total
1960	100
1961	100
1962	100
1963	100
1964	100
1965	100
1966	100
1967	80
1968	79.10112359550561
1969	76.68067226890756
1970	83.90313390313389
1971	93.7908496732026
1972	92.42937853107345
1973	93.75873311597577
1974	94.49131513647643
1975	97.68991559306976
1976	97.9013045944413
1977	99.62264150943396
1978	97.50277469478357
1979	96.77248677248677
1980	97.06287287746672
1981	97.12041884816755
1982	96.92058346839545
1983	99.45454545454545
1984	100
1985	100
1986	100
1987	100
1988	100
1989	99.81167608286253
1990	103.4176404494382
1991	97.91670212765958
1992	73.0501185770751
1993	83.64252380952381
1994	85.56333333333333
1995	83.56528846153846
1996	87.67294416243654
1997	85.97768361581922
1998	84.1633039647577
1999	87.4817937219731
2000	90.98957943925234
2001	87.45708920187793
2002	84.4375
2003	87.03013333333334
2004	90.99592592592593
2005	90.22272277227724
2006	87.68123762376237
2007	86.62623188405797
2008	111.74791469194312
2009	26.61925249169435
2010	114.59375
2011	74.249173553719
2012	52.184230769230766
2013	92.20559485530548
2014	89.57557251908398
2015	84.78970464135021
2016	81.37726027397261