Year	Percent
1971	103.27541
1972	99.46635
1973	97.48572
1974	97.31372
1975	97.32159
1976	97.77704
1977	101.65488
1978	97.35083
1979	89.16822
1980	103.76349
1981	102.35696
1982	98.01874
1983	97.40597
1984	98.01168
1985	98.30724
1986	100.27643
1987	101.62622
1988	99.64853
1989	99.75997
1990	102.0458
1991	101.8992
1992	99.66961
1994	97.0837
1998	99.78154
1999	98.92765
2000	98.44242
2001	98.69056
2002	96.12106
2003	96.02414
2004	98.54466
2005	99.05057
2006	99.00274
2007	102.52999
2009	100.50258
2010	99.98321
2011	101.68659
2012	101.54215