Year	Percent
1960	84.56741
1961	76.70457
1962	74.60282
1963	81.34937
1964	89.05978
1965	81.97346
1966	82.48597
1967	79.31145
1968	89.50489
1969	96.08408
1970	101.87263
1971	105.93822
1972	78.92559
1973	81.59803
1974	99.00886
1975	97.47363
1976	100.90331
1977	81.54076
1978	86.25046
1979	86.00748
1980	87.44196
1981	80.324
1982	85.26784
1983	90.79359
1984	97.01907
1985	97.49955
1986	93.87823
1987	86.00038
1988	103.12529
1989	94.06505
1990	91.11134
1991	80.83832
1992	75.55204
1993	66.71142
1994	62.18938
1995	56.01115
1996	53.39532
1997	67.28585
1998	65.03937
1999	63.98458
2000	52.99417
2001	52.87876
2002	45.89903
2003	49.66104
2004	50.22653
2005	50.89893
2006	50.64835
2007	57.4383
2008	61.16902
2009	56.68118
2010	55.70575
2011	54.74677
2012	57.59411
2013	58.12422
2014	56.47426
2015	50.15194
2016	49.8327
2017	43.69137