Year	Percent
1960	81.15693
1961	81.83464
1962	79.59285
1963	80.69181
1964	80.79417
1965	77.46693
1966	75.70007
1967	72.69016
1968	73.68844
1969	77.34288
1970	77.08316
1971	76.43758
1972	73.73065
1973	79.09254
1974	88.67034
1975	81.62561
1976	86.18636
1977	82.14991
1978	77.2752
1979	85.05539
1980	78.89438
1981	83.89689
1982	83.12004
1983	83.39723
1984	90.07298
1985	93.97512
1986	78.59515
1987	76.23013
1988	78.38835
1989	83.35609
1990	82.05521
1991	80.26217
1992	76.74063
1993	76.35706
1994	83.14965
1995	86.98271
1996	89.72804
1997	96.69189
1998	94.71402
1999	96.10063
2000	109.34806
2001	103.0285
2002	99.56037
2003	98.05081
2004	104.08178
2005	113.5087
2006	121.16742
2007	124.29666
2008	130.18779
2009	109.68737
2010	130.40089
2011	141.14204
2012	149.86495
2013	145.52697
2014	143.48128
2015	142.87475
2016	138.5055
2017	148.42742