1957 01 99.99 -99.99  26.50 
1957 02 99.99 -99.99  26.50 
1957 03 99.99 -99.99  26.30 
1957 04 99.99 -99.99  26.10 
1957 05 99.99 -99.99  26.80 
1957 06 99.99 -99.99  26.40 
1957 07 99.99 -99.99  26.50 
1957 08 99.99 -99.99  26.80 
1957 09 99.99 -99.99  26.60 
1957 10 99.99 -99.99  27.50 
1957 11 99.99 -99.99  27.40 
1957 12 99.99 -99.99  27.30 
1958 01 99.99 -99.99  27.50 
1958 02 99.99 -99.99  27.50 
1958 03 99.99 -99.99  27.10 
1958 04 99.99 -99.99  26.80 
1958 05 99.99 -99.99  27.90 
1958 06 99.99 -99.99  27.80 
1958 07 99.99 -99.99  27.20 
1959 02 99.99 -99.99  25.70 
1959 03 99.99 -99.99  26.10 
1959 04 99.99 -99.99  25.90 
1959 05 99.99 -99.99  26.50 
1959 06 99.99 -99.99  25.80 
1959 07 99.99 -99.99  25.70 
1959 08 99.99 -99.99  25.60 
1959 09 99.99 -99.99  25.80 
1959 10 99.99 -99.99  26.20 
1959 11 99.99 -99.99  26.00 
1959 12 99.99 -99.99  26.10 
1960 01 99.99 -99.99  25.50 
1960 02 99.99 -99.99  25.90 
1960 03 99.99 -99.99  25.60 
1960 07 99.99 -99.99  25.40 
1960 08 99.99 -99.99  25.50 
1960 09 99.99 -99.99  26.10 
1961 02 99.99 -99.99  27.50 
1961 03 99.99 -99.99  27.10 
1961 04 99.99 -99.99  27.50 
1961 06 99.99 -99.99  27.00 
1961 07 99.99 -99.99  26.40 
1961 08 99.99 -99.99  26.80 
1961 09 99.99 -99.99  26.90 
1961 10 99.99 -99.99  27.40 
1961 11 99.99 -99.99  27.20 
1961 12 99.99 -99.99  27.60 
1962 01 99.99 -99.99  28.20 
1962 02 99.99 -99.99  27.50 
1962 03 99.99 -99.99  27.40 
1962 05 99.99 -99.99  27.30 
1962 06 99.99 -99.99  26.90 
1962 07 99.99 -99.99  27.10 
1962 08 99.99 -99.99  27.00 
1962 09 99.99 -99.99  27.20 
1962 10 99.99 -99.99  27.90 
1962 11 99.99 -99.99  27.60 
1962 12 99.99 -99.99  27.00 
1963 01 99.99 -99.99  28.30 
1963 02 99.99 -99.99  27.90 
1963 03 99.99 -99.99  27.10 
1963 04 99.99 -99.99  27.30 
1963 05 99.99 -99.99  27.70 
1963 06 99.99 -99.99  27.10 
1963 07 99.99 -99.99  26.80 
1963 08 99.99 -99.99  27.20 
1963 09 99.99 -99.99  27.00 
1963 10 99.99 -99.99  27.00 
1963 11 99.99 -99.99  27.10 
1963 12 99.99 -99.99  27.20 
1964 01 99.99 -99.99  27.40 
1964 02 99.99 -99.99  27.50 
1964 03 99.99 -99.99  27.40 
1964 04 99.99 -99.99  27.90 
1964 05 99.99 -99.99  27.40 
1964 06 99.99 -99.99  27.20 
1964 07 99.99 -99.99  27.10 
1964 08 99.99 -99.99  27.00 
1964 09 99.99 -99.99  27.50 
1964 10 99.99 -99.99  27.60 
