1968 01 99.99 -99.99  15.00 
1968 02 99.99 -99.99  17.60 
1968 04 99.99 -99.99  29.70 
1968 05 99.99 -99.99  31.50 
1968 06 99.99 -99.99  33.20 
1968 07 99.99 -99.99  32.50 
1968 08 99.99 -99.99  30.70 
1968 09 99.99 -99.99  29.80 
1968 10 99.99 -99.99  28.40 
1968 11 99.99 -99.99  23.40 
1968 12 99.99 -99.99  17.60 
1969 02 99.99 -99.99  19.40 
1969 03 99.99 -99.99  26.60 
1969 04 99.99 -99.99  30.40 
1969 05 99.99 -99.99  32.50 
1969 06 99.99 -99.99  33.40 
1969 07 99.99 -99.99  32.30 
1969 08 99.99 -99.99  30.00 
1969 09 99.99 -99.99  30.30 
1969 10 99.99 -99.99  29.50 
1969 11 99.99 -99.99  23.60 
1969 12 99.99 -99.99  18.29 
1970 01 99.99 -99.99  16.50 
1970 02 99.99 -99.99  19.10 
1970 03 99.99 -99.99  24.00 
1970 04 99.99 -99.99  29.70 
1970 05 99.99 -99.99  33.20 
1970 06 99.99 -99.99  33.30 
1970 07 99.99 -99.99  31.10 
1970 08 99.99 -99.99  30.40 
1970 09 99.99 -99.99  29.10 
1970 10 99.99 -99.99  27.30 
1970 11 99.99 -99.99  20.60 
1970 12 99.99 -99.99  16.50 
1971 04 99.99 -99.99  31.70 
1971 05 99.99 -99.99  32.30 
1971 06 99.99 -99.99  32.59 
1971 07 99.99 -99.99  30.70 
1971 08 99.99 -99.99  30.10 
1971 09 99.99 -99.99  30.50 
1971 10 99.99 -99.99  27.40 
1971 11 99.99 -99.99  22.40 
1972 03 99.99 -99.99  24.90 
1972 04 99.99 -99.99  28.70 
1972 05 99.99 -99.99  32.80 
1972 06 99.99 -99.99  33.50 
1972 07 99.99 -99.99  31.50 
1972 08 99.99 -99.99  31.40 
1972 09 99.99 -99.99  30.30 
1972 10 99.99 -99.99  28.60 
1972 11 99.99 -99.99  23.60 
1972 12 99.99 -99.99  17.40 
1973 01 99.99 -99.99  14.80 
1973 02 99.99 -99.99  20.60 
1973 03 99.99 -99.99  24.70 
1973 04 99.99 -99.99  31.00 
1973 05 99.99 -99.99  34.00 
1973 06 99.99 -99.99  32.90 
1973 07 99.99 -99.99  32.90 
1973 08 99.99 -99.99  30.90 
1973 09 99.99 -99.99  30.20 
1973 10 99.99 -99.99  27.90 
1973 11 99.99 -99.99  21.80 
1973 12 99.99 -99.99  15.80 
1974 01 99.99 -99.99  14.80 
1974 02 99.99 -99.99  16.10 
1974 03 99.99 -99.99  26.20 
1974 04 99.99 -99.99  30.20 
1974 05 99.99 -99.99  32.80 
1974 06 99.99 -99.99  32.09 
1974 07 99.99 -99.99  31.80 
1974 08 99.99 -99.99  31.10 
1974 09 99.99 -99.99  31.60 
1974 10 99.99 -99.99  28.70 
1974 11 99.99 -99.99  22.50 
1974 12 99.99 -99.99  15.50 
