year  ismidx-jja
1948   0.020
1949  -2.514
1950  -1.370
1951  -0.269
1952   0.840
1953   0.365
1954   0.639
1955  -0.238
1956   0.837
1957   0.859
1958   0.848
1959   1.749
1960   0.406
1961   1.323
1962  -1.020
1963  -0.530
1964  -0.198
1965  -2.103
1966  -1.672
1967   0.628
1968  -0.904
1969  -1.007
1970   1.490
1971  -0.114
1972  -1.885
1973   1.208
1974  -1.596
1975   1.352
1976  -0.297
1977   0.455
1978   1.613
1979  -0.725
1980   1.770
1981  -0.395
1982  -0.098
1983   0.556
1984   0.140
1985  -0.943
1986  -0.210
1987  -1.710
1988   0.253
1989   0.428
1990  -0.080
1991   0.503
1992   0.609
1993  -0.236
1994   1.839
1995  -1.014
1996   0.709
1997  -1.011
1998  -0.037
1999  -1.148
2000   0.425
2001   0.548
2002  -0.812
2003   0.477
2004   0.403
2005   0.230
2006   0.373
2007   0.243