1971 11 99.99 -99.99  27.70 
1971 12 99.99 -99.99  27.10 
1972 01 99.99 -99.99  25.20 
1972 02 99.99 -99.99  25.50 
1972 04 99.99 -99.99  26.00 
1972 05 99.99 -99.99  26.60 
1972 06 99.99 -99.99  26.40 
1972 07 99.99 -99.99  26.80 
1972 09 99.99 -99.99  27.70 
1972 10 99.99 -99.99  28.50 
1972 11 99.99 -99.99  27.30 
1972 12 99.99 -99.99  26.70 
1973 01 99.99 -99.99  27.00 
1973 02 99.99 -99.99  26.60 
1973 03 99.99 -99.99  26.90 
1973 04 99.99 -99.99  27.40 
1973 05 99.99 -99.99  26.40 
1973 06 99.99 -99.99  26.30 
1973 07 99.99 -99.99  26.80 
1973 08 99.99 -99.99  27.70 
1973 09 99.99 -99.99  27.10 
1973 10 99.99 -99.99  27.60 
1973 11 99.99 -99.99  27.60 
1973 12 99.99 -99.99  26.00 
1974 01 99.99 -99.99  25.30 
1974 02 99.99 -99.99  25.90 
1974 03 99.99 -99.99  26.40 
1974 04 99.99 -99.99  27.20 
1974 05 99.99 -99.99  27.50 
1974 06 99.99 -99.99  26.50 
1974 07 99.99 -99.99  26.80 
1974 08 99.99 -99.99  27.50 
1974 09 99.99 -99.99  27.70 
1974 10 99.99 -99.99  28.00 
1974 11 99.99 -99.99  27.20 
1974 12 99.99 -99.99  26.50 
1975 01 99.99 -99.99  25.60 
1975 02 99.99 -99.99  25.60 
1975 03 99.99 -99.99  26.40 
1975 04 99.99 -99.99  27.00 
1975 05 99.99 -99.99  26.50 
1975 07 99.99 -99.99  26.00 
1975 08 99.99 -99.99  27.20 
1975 09 99.99 -99.99  28.00 
1975 10 99.99 -99.99  28.20 
1975 11 99.99 -99.99  27.50 
1976 01 99.99 -99.99  25.40 
1976 03 99.99 -99.99  25.30 
1976 04 99.99 -99.99  25.90 
1976 05 99.99 -99.99  25.70 
1976 06 99.99 -99.99  25.90 
1976 07 99.99 -99.99  26.00 
1976 08 99.99 -99.99  27.60 
1976 09 99.99 -99.99  28.80 
1976 10 99.99 -99.99  30.30 
1976 11 99.99 -99.99  28.50 
1976 12 99.99 -99.99  26.20 
1977 01 99.99 -99.99  26.70 
1977 02 99.99 -99.99  26.10 
1977 03 99.99 -99.99  26.20 
1977 04 99.99 -99.99  26.70 
1977 05 99.99 -99.99  26.60 
1977 06 99.99 -99.99  26.50 
1977 07 99.99 -99.99  26.90 
1977 08 99.99 -99.99  27.50 
1977 09 99.99 -99.99  27.40 
1977 10 99.99 -99.99  28.40 
1977 11 99.99 -99.99  27.80 
1977 12 99.99 -99.99  26.50 
1978 01 99.99 -99.99  26.20 
1978 02 99.99 -99.99  26.70 
1978 03 99.99 -99.99  27.00 
1978 04 99.99 -99.99  27.20 
1978 05 99.99 -99.99  26.90 
1978 06 99.99 -99.99  26.80 
1978 07 99.99 -99.99  27.00 
1978 08 99.99 -99.99  27.50 
1978 09 99.99 -99.99  28.10 
1978 10 99.99 -99.99  28.20 
1978 11 99.99 -99.99  28.30 
1978 12 99.99 -99.99  26.00 
1979 01 99.99 -99.99  26.70 
1979 02 99.99 -99.99  26.70 
1979 03 99.99 -99.99  26.90 
1979 04 99.99 -99.99  26.80 
1979 05 99.99 -99.99  27.40 
1979 06 99.99 -99.99  26.70 
1979 07 99.99 -99.99  27.50 
1979 08 99.99 -99.99  28.10 
1979 09 99.99 -99.99  28.50 
1979 10 99.99 -99.99  28.90 
1979 11 99.99 -99.99  28.60 
1979 12 99.99 -99.99  27.00 
1980 01 99.99 -99.99  27.10 
1980 02 99.99 -99.99  27.40 
1980 03 99.99 -99.99  26.30 
1980 04 99.99 -99.99  26.90 
1980 05 99.99 -99.99  26.90 
1980 06 99.99 -99.99  27.30 
1980 07 99.99 -99.99  27.20 
1980 08 99.99 -99.99  28.10 
1980 09 99.99 -99.99  29.10 
1980 10 99.99 -99.99  28.00 
1980 11 99.99 -99.99  27.70 
1980 12 99.99 -99.99  27.30 
