Year	Percent
1960	38.46154
1961	45.4902
1962	47.82609
1963	50.89286
1964	49.59569
1965	53.31633
1966	56.54321
1967	56.69738
1968	55.13784
1969	51.57046
1970	48.87984
1971	54.84461
1972	69.13183
1973	67.77646
1974	77.07317
1975	103.9783
1976	138.62928
1977	112.43308
1978	90.59534
1979	123.6185
1980	110.08628
1981	117.00787
2007	103.28457
2008	102.20313
2009	106.48131
2010	101.11444
2011	94.42051
2012	100.30995
2013	89.07819
2014	82.29327
2015	81.76524
2016	83.1333