1951 01 99.99 -99.99  21.40 
1951 02 99.99 -99.99  21.90 
1951 03 99.99 -99.99  22.80 
1951 04 99.99 -99.99  22.20 
1951 05 99.99 -99.99  22.80 
1951 06 99.99 -99.99  21.90 
1951 07 99.99 -99.99  21.50 
1951 08 99.99 -99.99  21.60 
1951 09 99.99 -99.99  21.20 
1951 10 99.99 -99.99  22.20 
1951 11 99.99 -99.99  21.50 
1951 12 99.99 -99.99  21.10 
1952 01 99.99 -99.99  22.50 
1952 02 99.99 -99.99  23.20 
1952 03 99.99 -99.99  23.30 
1952 04 99.99 -99.99  22.80 
1952 05 99.99 -99.99  22.60 
1952 06 99.99 -99.99  22.30 
1952 07 99.99 -99.99  21.60 
1952 08 99.99 -99.99  21.10 
1952 09 99.99 -99.99  21.40 
1952 10 99.99 -99.99  21.90 
1952 11 99.99 -99.99  21.70 
1952 12 99.99 -99.99  22.70 
1953 01 99.99 -99.99  22.50 
1953 02 99.99 -99.99  23.20 
1953 03 99.99 -99.99  23.40 
1953 04 99.99 -99.99  22.60 
1953 05 99.99 -99.99  23.40 
1953 06 99.99 -99.99  21.90 
1953 07 99.99 -99.99  21.00 
1953 08 99.99 -99.99  21.50 
1953 09 99.99 -99.99  21.40 
1953 10 99.99 -99.99  21.30 
1953 11 99.99 -99.99  21.90 
1953 12 99.99 -99.99  22.30 
1954 01 99.99 -99.99  23.20 
1954 02 99.99 -99.99  23.00 
1954 03 99.99 -99.99  23.00 
1954 04 99.99 -99.99  22.80 
1954 05 99.99 -99.99  22.20 
1954 06 99.99 -99.99  21.50 
1954 07 99.99 -99.99  20.90 
1954 08 99.99 -99.99  20.90 
1954 09 99.99 -99.99  21.00 
1954 10 99.99 -99.99  20.90 
1954 11 99.99 -99.99  22.20 
1954 12 99.99 -99.99  22.00 
1955 01 99.99 -99.99  22.20 
1955 02 99.99 -99.99  22.20 
1955 03 99.99 -99.99  22.40 
1955 04 99.99 -99.99  22.80 
1955 05 99.99 -99.99  22.60 
1955 06 99.99 -99.99  21.90 
1955 07 99.99 -99.99  21.30 
1955 08 99.99 -99.99  21.00 
1955 09 99.99 -99.99  21.50 
1955 10 99.99 -99.99  21.70 
1955 11 99.99 -99.99  21.90 
1955 12 99.99 -99.99  21.50 
1956 01 99.99 -99.99  22.10 
1956 02 99.99 -99.99  22.40 
1956 03 99.99 -99.99  22.70 
1956 04 99.99 -99.99  22.10 
1956 05 99.99 -99.99  22.20 
1956 06 99.99 -99.99  21.50 
1956 07 99.99 -99.99  20.60 
1956 08 99.99 -99.99  21.00 
