1972 01 99.99 -99.99  19.50 
1972 03 99.99 -99.99  24.80 
1972 05 99.99 -99.99  28.70 
1972 06 99.99 -99.99  28.00 
1972 07 99.99 -99.99  27.00 
1972 09 99.99 -99.99  27.40 
1972 10 99.99 -99.99  26.60 
1972 11 99.99 -99.99  24.60 
1972 12 99.99 -99.99  21.00 
1973 01 99.99 -99.99  21.30 
1973 03 99.99 -99.99  25.80 
1973 04 99.99 -99.99  28.40 
1973 05 99.99 -99.99  28.00 
1973 06 99.99 -99.99  28.00 
1973 08 99.99 -99.99  26.80 
1973 09 99.99 -99.99  26.60 
1973 10 99.99 -99.99  26.00 
1973 11 99.99 -99.99  22.70 
1973 12 99.99 -99.99  19.40 
1974 01 99.99 -99.99  19.40 
1974 02 99.99 -99.99  22.10 
1974 03 99.99 -99.99  24.80 
1974 04 99.99 -99.99  26.70 
1974 05 99.99 -99.99  27.70 
1974 06 99.99 -99.99  27.60 
1974 07 99.99 -99.99  27.40 
1974 08 99.99 -99.99  27.90 
1974 09 99.99 -99.99  27.80 
1974 10 99.99 -99.99  27.80 
1974 11 99.99 -99.99  25.10 
1974 12 99.99 -99.99  22.80 
1975 01 99.99 -99.99  21.80 
1975 02 99.99 -99.99  24.00 
1975 03 99.99 -99.99  26.70 
1975 04 99.99 -99.99  29.10 
1975 05 99.99 -99.99  31.80 
1975 06 99.99 -99.99  31.00 
1975 07 99.99 -99.99  28.90 
1975 08 99.99 -99.99  26.20 
1975 09 99.99 -99.99  25.50 
1975 10 99.99 -99.99  23.70 
1975 11 99.99 -99.99  22.40 
1976 01 99.99 -99.99  18.60 
