Year	Percent
1971	86.77827
1972	87.6234
1973	84.2855
1974	86.29269
1975	79.3071
1976	79.86982
1977	73.05708
1978	78.46882
1979	84.04483
1980	72.71665
1981	88.47539
1982	76.69648
1983	78.37119
1984	75.75218
1985	57.83026
1986	61.59292
1987	68.30484
1988	80.194
1989	79.8235
1990	78.48378
1991	82.77481
1992	83.64318
1993	100.96061
1994	103.97086
1995	99.5756
1996	98.12467
1997	98.53899
1999	101.56877
2000	98.02643
2001	97.55493
2002	100.01796
2003	99.36486
2004	88.09077
2005	100.30179
2006	100.89286
2007	99.94413
2008	100.78695
2009	103.00226
2010	97.87958
2011	101.91151
2012	100.41382
2013	98.78904
2014	99.57542
2015	95.89254