year  ismidx-jjas
1948   0.477
1949  -1.580
1950  -0.545
1951  -0.642
1952   0.041
1953   0.029
1954   1.387
1955   0.194
1956   1.258
1957   0.516
1958   0.985
1959   2.120
1960   0.901
1961   1.733
1962  -0.129
1963  -0.579
1964   0.380
1965  -2.099
1966  -2.072
1967   0.381
1968  -0.692
1969  -0.794
1970   1.489
1971  -0.326
1972  -2.219
1973   0.972
1974  -1.266
1975   1.519
1976  -0.398
1977   0.165
1978   0.987
1979  -0.912
1980   0.826
1981   0.033
1982  -0.600
1983   1.072
1984  -0.815
1985  -1.093
1986  -0.546
1987  -2.069
1988   0.813
1989  -0.108
1990  -0.064
1991  -0.266
1992   0.279
1993  -0.047
1994   1.183
1995  -0.748
1996   0.422
1997  -1.431
1998   0.608
1999  -0.830
2000  -0.050
2001  -0.098
2002  -1.111
2003   0.320
2004   0.112
2005   1.063
2006   0.954
2007   0.912