1977 04 99.99 -99.99  26.80 
1977 05 99.99 -99.99  26.40 
1977 06 99.99 -99.99  26.20 
1977 07 99.99 -99.99  26.20 
1977 08 99.99 -99.99  25.50 
1977 09 99.99 -99.99  29.80 
1977 10 99.99 -99.99  26.50 
1977 11 99.99 -99.99  28.70 
1977 12 99.99 -99.99  28.10 
1978 04 99.99 -99.99  27.10 
1978 05 99.99 -99.99  27.30 
1978 09 99.99 -99.99  25.60 
1978 10 99.99 -99.99  25.00 
1978 11 99.99 -99.99  27.50 
1978 12 99.99 -99.99  27.10 
1979 01 99.99 -99.99  26.90 
1979 02 99.99 -99.99  27.20 
1979 03 99.99 -99.99  26.10 
1979 05 99.99 -99.99  28.10 
1979 06 99.99 -99.99  27.30 
1979 07 99.99 -99.99  26.90 
1979 08 99.99 -99.99  26.90 
1979 09 99.99 -99.99  27.10 
1979 10 99.99 -99.99  27.00 
1979 11 99.99 -99.99  31.00 
1979 12 99.99 -99.99  25.70 
1980 01 99.99 -99.99  26.60 
1980 02 99.99 -99.99  26.40 
1980 03 99.99 -99.99  27.30 
1980 04 99.99 -99.99  26.90 
1980 05 99.99 -99.99  27.00 
1980 06 99.99 -99.99  26.80 
1980 07 99.99 -99.99  26.10 
1980 08 99.99 -99.99  26.10 
1980 09 99.99 -99.99  25.90 
1980 10 99.99 -99.99  26.30 
1980 11 99.99 -99.99  26.90 
1981 02 99.99 -99.99  26.80 
1981 03 99.99 -99.99  26.70 
1981 04 99.99 -99.99  26.90 
1982 06 99.99 -99.99  26.50 
1982 08 99.99 -99.99  25.30 
1982 09 99.99 -99.99  25.00 
1982 10 99.99 -99.99  25.30 
1982 11 99.99 -99.99  26.40 
1983 02 99.99 -99.99  26.80 
1983 03 99.99 -99.99  27.20 
1983 04 99.99 -99.99  27.40 
1983 05 99.99 -99.99  25.70 
1983 07 99.99 -99.99  27.00 
1983 08 99.99 -99.99  27.00 
1983 09 99.99 -99.99  26.60 
1983 10 99.99 -99.99  26.80 
1983 12 99.99 -99.99  26.90 
1984 01 99.99 -99.99  26.80 
1984 02 99.99 -99.99  26.60 
1984 03 99.99 -99.99  27.00 
1984 04 99.99 -99.99  26.70 
1984 06 99.99 -99.99  29.70 
1984 07 99.99 -99.99  26.30 
1984 08 99.99 -99.99  25.90 
1985 01 99.99 -99.99  27.00 
1995 10 31.50  21.80  26.65 
1996 01 30.70 -99.99 -99.99 
1996 07 30.20  22.20  26.20 
1997 02 30.50  21.60  26.05 
1997 07 29.60  27.00  28.30 
2000 09 30.40    .80  15.60 
