1971 01 99.99 -99.99  12.70 
1971 02 99.99 -99.99  13.70 
1971 03 99.99 -99.99  17.90 
1971 04 99.99 -99.99  22.60 
1971 05 99.99 -99.99  31.70 
1971 06 99.99 -99.99  32.70 
1971 07 99.99 -99.99  35.80 
1971 08 99.99 -99.99  35.00 
1971 09 99.99 -99.99  31.70 
1971 10 99.99 -99.99  24.50 
1971 11 99.99 -99.99  18.79 
1971 12 99.99 -99.99  11.50 
1972 01 99.99 -99.99   9.10 
1972 02 99.99 -99.99  11.10 
1972 03 99.99 -99.99  16.70 
1972 04 99.99 -99.99  23.50 
1972 05 99.99 -99.99  26.80 
1972 06 99.99 -99.99  33.30 
1972 07 99.99 -99.99  35.30 
1972 08 99.99 -99.99  35.50 
1972 09 99.99 -99.99  31.90 
1972 10 99.99 -99.99  27.10 
1972 11 99.99 -99.99  17.00 
1972 12 99.99 -99.99   8.39 
1973 01 99.99 -99.99   9.80 
1973 02 99.99 -99.99  15.40 
1973 03 99.99 -99.99  18.10 
1973 04 99.99 -99.99  24.00 
1973 05 99.99 -99.99  31.20 
1973 06 99.99 -99.99  34.20 
1973 07 99.99 -99.99  35.59 
1973 08 99.99 -99.99  36.59 
1973 09 99.99 -99.99  32.70 
1973 10 99.99 -99.99  26.80 
1973 11 99.99 -99.99  15.80 
1973 12 99.99 -99.99  11.60 
1974 01 99.99 -99.99   9.39 
1974 02 99.99 -99.99  11.60 
1974 03 99.99 -99.99  17.70 
1974 04 99.99 -99.99  21.30 
1974 05 99.99 -99.99  30.00 
1974 06 99.99 -99.99  33.20 
1974 07 99.99 -99.99  35.09 
1974 08 99.99 -99.99  34.00 
1974 09 99.99 -99.99  31.30 
1974 10 99.99 -99.99  24.80 
1974 11 99.99 -99.99  20.40 
1974 12 99.99 -99.99  11.30 
1975 01 99.99 -99.99   9.30 
1975 02 99.99 -99.99  12.70 
1975 03 99.99 -99.99  16.90 
1975 04 99.99 -99.99  24.10 
1975 05 99.99 -99.99  30.40 
1975 06 99.99 -99.99  34.00 
1975 07 99.99 -99.99  36.50 
1975 08 99.99 -99.99  34.80 
1975 09 99.99 -99.99  33.40 
1975 10 99.99 -99.99  23.10 
1975 11 99.99 -99.99  17.29 
1975 12 99.99 -99.99  10.70 
1976 01 99.99 -99.99  10.80 
1976 02 99.99 -99.99  11.60 
1976 03 99.99 -99.99  15.10 
1976 04 99.99 -99.99  22.60 
1976 05 99.99 -99.99  28.70 
1976 06 99.99 -99.99  34.80 
1976 07 99.99 -99.99  34.50 
1976 08 99.99 -99.99  34.20 
1976 09 99.99 -99.99  31.40 
1976 10 99.99 -99.99  26.20 
1976 11 99.99 -99.99  18.10 
1976 12 99.99 -99.99  14.70 
1977 01 99.99 -99.99   8.10 
1977 02 99.99 -99.99  15.40 
1977 03 99.99 -99.99  19.00 
1977 04 99.99 -99.99  23.40 
1977 05 99.99 -99.99  31.20 
1977 06 99.99 -99.99  34.40 
1977 07 99.99 -99.99  36.09 
1977 08 99.99 -99.99  36.20 
1977 09 99.99 -99.99  32.90 
1977 10 99.99 -99.99  23.60 
1977 11 99.99 -99.99  16.50 
1977 12 99.99 -99.99  13.70 
1978 01 99.99 -99.99  12.20 
1978 02 99.99 -99.99  14.90 
1978 03 99.99 -99.99  18.10 
1978 04 99.99 -99.99  24.70 
1978 05 99.99 -99.99  30.20 
1978 06 99.99 -99.99  35.09 
1978 07 99.99 -99.99  36.30 
1978 08 99.99 -99.99  33.80 
1978 09 99.99 -99.99  32.09 
1978 10 99.99 -99.99  26.50 
1978 11 99.99 -99.99  14.30 
1978 12 99.99 -99.99  14.80 
1979 01 99.99 -99.99  12.50 
1979 02 99.99 -99.99  16.00 
1979 03 99.99 -99.99  18.10 
1979 04 99.99 -99.99  25.50 
1979 05 99.99 -99.99  29.90 
1979 06 99.99 -99.99  33.50 
1979 07 99.99 -99.99  36.50 
1979 08 99.99 -99.99  35.30 
1979 09 99.99 -99.99  33.09 
1979 10 99.99 -99.99  26.80 
1979 11 99.99 -99.99  20.20 
1979 12 99.99 -99.99  11.60 
1980 01 99.99 -99.99  10.40 
1980 02 99.99 -99.99  12.50 
1980 03 99.99 -99.99  19.10 
1980 04 99.99 -99.99  25.20 
1980 05 99.99 -99.99  30.30 
1980 06 99.99 -99.99  35.50 
1980 07 99.99 -99.99  37.90 
1980 08 99.99 -99.99  35.30 
1980 09 99.99 -99.99  31.30 
1980 10 99.99 -99.99  25.90 
1980 11 99.99 -99.99  19.29 
1980 12 99.99 -99.99  12.60 
