year  ismidx-jja
1948   0.227
1949  -2.676
1950  -1.180
1951  -0.302
1952   1.027
1953   0.234
1954   0.254
1955  -0.365
1956   0.868
1957   0.826
1958   1.129
1959   1.543
1960   0.137
1961   1.166
1962  -1.050
1963  -0.523
1964  -0.486
1965  -1.967
1966  -1.192
1967   0.462
1968  -0.741
1969  -0.813
1970   1.457
1971   0.173
1972  -1.904
1973   1.165
1974  -1.705
1975   1.246
1976  -0.365
1977   0.427
1978   1.583
1979  -1.040
1980   1.871
1981  -0.386
1982  -0.138
1983   0.533
1984   0.261
1985  -0.821
1986  -0.205
1987  -1.879
1988   0.105
1989   0.561
1990   0.355
1991   0.889
1992   0.819
1993  -0.181
1994   1.969
1995  -0.694
1996   0.818
1997  -0.868
1998  -0.105
1999  -1.058
2000   0.801
2001   0.660
2002  -0.794
2003   0.419
2004   0.348
2005   0.139
2006   0.358
2007  -0.217
2008  -1.172