Year	Percent
1971	97.03231
1972	99.30123
1973	99.22797
1974	100.26406
1975	107.89683
1976	106.01702
1977	105.5424
1978	102.47713
1979	101.58152
1980	103.40712
1981	100.3099
1982	101.11102
1983	99.96778
1984	100.28917
1985	102.17178
1986	101.85955
1987	99.75363
1988	99.69272
1989	100.16505
1990	100.66354
1991	97.76532
1992	98.67724
1994	101.82617
1995	97.56691
1996	98.68838
1997	95.4299
1999	99.46982
2000	100.74278
2001	103.35809
2002	101.6454
2003	101.98478
2004	100.66274
2005	98.78251
2006	98.80285
2007	100.80997
2008	104.43297
2009	101.53002
2010	102.45861
2011	103.19342
2012	100.05132
2013	99.8374
2014	99.934
2015	100.28283