1971 06 99.99 -99.99  25.40 
1971 07 99.99 -99.99  26.10 
1971 08 99.99 -99.99  25.00 
1972 06 99.99 -99.99  26.40 
1972 07 99.99 -99.99  27.60 
1972 08 99.99 -99.99  25.80 
1972 09 99.99 -99.99  26.20 
1972 10 99.99 -99.99  25.80 
1972 11 99.99 -99.99  26.60 
1972 12 99.99 -99.99  26.20 
1973 06 99.99 -99.99  26.60 
1973 07 99.99 -99.99  25.80 
1973 08 99.99 -99.99  24.70 
1973 09 99.99 -99.99  24.00 
1973 10 99.99 -99.99  23.60 
1973 12 99.99 -99.99  24.40 
1974 10 99.99 -99.99  26.30 
1974 11 99.99 -99.99  27.00 
1975 01 99.99 -99.99  28.50 
1975 05 99.99 -99.99  26.60 
1975 06 99.99 -99.99  25.80 
1975 07 99.99 -99.99  25.20 
1975 08 99.99 -99.99  25.50 
1975 09 99.99 -99.99  25.50 
1976 09 99.99 -99.99  26.80 
1976 10 99.99 -99.99  26.20 
1976 11 99.99 -99.99  26.50 
1976 12 99.99 -99.99  27.50 
1977 01 99.99 -99.99  27.80 
1977 02 99.99 -99.99  28.60 
1977 03 99.99 -99.99  29.40 
1977 04 99.99 -99.99  29.60 
1977 05 99.99 -99.99  28.10 
1977 06 99.99 -99.99  26.70 
1977 07 99.99 -99.99  27.70 
1977 08 99.99 -99.99  26.70 
1977 09 99.99 -99.99  26.10 
1977 10 99.99 -99.99  27.00 
1977 11 99.99 -99.99  26.60 
1977 12 99.99 -99.99  27.40 
1978 01 99.99 -99.99  28.00 
1978 02 99.99 -99.99  28.80 
1978 03 99.99 -99.99  29.00 
1978 04 99.99 -99.99  28.20 
1978 05 99.99 -99.99  27.20 
1978 06 99.99 -99.99  26.20 
1978 07 99.99 -99.99  26.80 
1978 08 99.99 -99.99  26.60 
1978 09 99.99 -99.99  26.20 
1978 10 99.99 -99.99  26.10 
1978 11 99.99 -99.99  26.70 
1978 12 99.99 -99.99  27.00 
1979 01 99.99 -99.99  27.40 
1979 02 99.99 -99.99  29.00 
1979 03 99.99 -99.99  28.60 
1979 04 99.99 -99.99  28.00 
1979 05 99.99 -99.99  27.30 
1979 06 99.99 -99.99  25.80 
1979 07 99.99 -99.99  26.80 
1979 08 99.99 -99.99  26.60 
1979 09 99.99 -99.99  26.20 
1979 10 99.99 -99.99  26.00 
1979 11 99.99 -99.99  26.10 
1979 12 99.99 -99.99  27.10 
1980 01 99.99 -99.99  27.20 
1980 02 99.99 -99.99  28.10 
1980 03 99.99 -99.99  28.50 
1980 04 99.99 -99.99  28.80 
1980 05 99.99 -99.99  27.40 
1980 06 99.99 -99.99  26.70 
1980 07 99.99 -99.99  26.30 
1980 08 99.99 -99.99  26.50 
1980 09 99.99 -99.99  26.20 
1980 10 99.99 -99.99  26.20 
1980 11 99.99 -99.99  26.20 
1980 12 99.99 -99.99  26.30 
