year  ismidx-sep
1948   0.954
1949   0.794
1950   1.086
1951  -0.895
1952  -1.273
1953  -0.529
1954   1.837
1955   0.787
1956   1.250
1957  -0.319
1958   0.667
1959   1.558
1960   1.208
1961   1.446
1962   1.381
1963  -0.342
1964   1.105
1965  -0.944
1966  -1.582
1967  -0.228
1968   0.030
1969  -0.015
1970   0.672
1971  -0.489
1972  -1.542
1973   0.059
1974  -0.038
1975   0.958
1976  -0.344
1977  -0.395
1978  -0.565
1979  -0.714
1980  -1.153
1981   0.706
1982  -1.082
1983   1.318
1984  -1.912
1985  -0.736
1986  -0.791
1987  -1.517
1988   1.272
1989  -0.915
1990  -0.003
1991  -1.363
1992  -0.406
1993   0.284
1994  -0.527
1995   0.092
1996  -0.272
1997  -1.326
1998   1.319
1999   0.138
2000  -0.792
2001  -1.089
2002  -0.985
2003  -0.110
2004  -0.419
2005   1.826
2006   1.371
2007   1.494