1968 01 99.99 -99.99  24.50 
1968 02 99.99 -99.99  24.30 
1968 03 99.99 -99.99  18.20 
1968 04 99.99 -99.99  13.60 
1968 05 99.99 -99.99  10.60 
1968 06 99.99 -99.99   8.50 
1968 07 99.99 -99.99   9.10 
1968 08 99.99 -99.99   9.39 
1968 09 99.99 -99.99  13.10 
1968 10 99.99 -99.99  14.50 
1968 11 99.99 -99.99  21.90 
1968 12 99.99 -99.99  21.80 
1969 01 99.99 -99.99  25.40 
1969 02 99.99 -99.99  23.10 
1969 03 99.99 -99.99  18.90 
1969 05 99.99 -99.99  11.50 
1969 07 99.99 -99.99   8.00 
1969 08 99.99 -99.99   8.70 
1969 09 99.99 -99.99  12.50 
1969 10 99.99 -99.99  15.10 
1969 11 99.99 -99.99  20.20 
1969 12 99.99 -99.99  25.20 
1970 01 99.99 -99.99  23.20 
1970 02 99.99 -99.99  23.10 
1970 03 99.99 -99.99  20.00 
1970 04 99.99 -99.99  16.90 
1970 05 99.99 -99.99  13.90 
1970 06 99.99 -99.99   6.70 
1970 07 99.99 -99.99   7.40 
1970 08 99.99 -99.99   8.60 
1970 09 99.99 -99.99  14.10 
1970 10 99.99 -99.99  16.00 
1970 11 99.99 -99.99  18.60 
1970 12 99.99 -99.99  21.90 
1971 01 99.99 -99.99  23.40 
1971 02 99.99 -99.99  22.20 
1971 03 99.99 -99.99  20.80 
1971 04 99.99 -99.99  11.90 
1971 05 99.99 -99.99   9.10 
1971 06 99.99 -99.99   4.69 
1971 07 99.99 -99.99   8.60 
1971 08 99.99 -99.99   8.70 
1971 09 99.99 -99.99  13.10 
1971 10 99.99 -99.99  16.60 
1972 02 99.99 -99.99  23.20 
1972 03 99.99 -99.99  18.10 
1972 04 99.99 -99.99  14.70 
1972 05 99.99 -99.99  11.00 
1972 06 99.99 -99.99   7.00 
1972 07 99.99 -99.99   6.80 
1972 08 99.99 -99.99   7.40 
1972 09 99.99 -99.99  11.90 
1972 10 99.99 -99.99  13.90 
1973 01 99.99 -99.99  23.20 
1973 05 99.99 -99.99   8.39 
1973 06 99.99 -99.99   7.70 
1973 07 99.99 -99.99   4.80 
1973 08 99.99 -99.99   7.40 
1973 09 99.99 -99.99  10.10 
1973 10 99.99 -99.99  15.20 
1974 01 99.99 -99.99  23.40 
1974 02 99.99 -99.99  21.50 
1974 03 99.99 -99.99  27.00 
1974 04 99.99 -99.99  16.00 
1974 05 99.99 -99.99  10.50 
1974 06 99.99 -99.99   6.20 
1974 07 99.99 -99.99   6.30 
1974 11 99.99 -99.99  18.79 
1974 12 99.99 -99.99  20.40 
1975 02 99.99 -99.99  21.90 
1975 03 99.99 -99.99  16.60 
1975 04 99.99 -99.99  14.00 
1975 05 99.99 -99.99  10.80 
1975 06 99.99 -99.99   8.30 
1975 07 99.99 -99.99   4.90 
1975 08 99.99 -99.99   7.30 
1975 09 99.99 -99.99  12.10 
1975 10 99.99 -99.99  15.90 
1975 11 99.99 -99.99  18.29 
1975 12 99.99 -99.99  23.70 
1976 01 99.99 -99.99  24.30 
1976 02 99.99 -99.99  22.00 
1976 03 99.99 -99.99  17.00 
1977 11 99.99 -99.99  16.40 
