year  ismidx-sep
1948   1.009
1949   1.113
1950   1.370
1951  -0.934
1952  -1.285
1953  -0.448
1954   1.933
1955   0.661
1956   1.321
1957  -0.393
1958   0.894
1959   1.571
1960   1.084
1961   1.393
1962   1.350
1963  -0.384
1964   1.061
1965  -0.959
1966  -1.203
1967  -0.307
1968  -0.101
1969   0.209
1970   0.602
1971  -0.499
1972  -1.458
1973   0.058
1974  -0.272
1975   0.885
1976  -0.489
1977  -0.389
1978  -0.525
1979  -0.899
1980  -1.095
1981   0.794
1982  -1.247
1983   1.336
1984  -1.886
1985  -0.799
1986  -0.704
1987  -1.559
1988   1.186
1989  -1.005
1990   0.003
1991  -1.372
1992  -0.536
1993   0.505
1994  -0.711
1995   0.222
1996  -0.234
1997  -1.436
1998   1.500
1999   0.165
2000  -0.702
2001  -1.067
2002  -0.803
2003  -0.048
2004  -0.560
2005   1.750
2006   1.149
2007   1.384
2008  -0.199