1981 01 99.99 -99.99  21.20 
1981 02 99.99 -99.99  23.30 
1981 03 99.99 -99.99  25.00 
1981 04 99.99 -99.99  24.60 
1981 05 99.99 -99.99  25.70 
1981 06 99.99 -99.99  24.80 
1981 07 99.99 -99.99  24.10 
1981 08 99.99 -99.99  24.80 
1981 09 99.99 -99.99  25.20 
1981 10 99.99 -99.99  24.80 
1981 11 99.99 -99.99  23.00 
1981 12 99.99 -99.99  22.90 
1982 01 99.99 -99.99  23.30 
1982 02 99.99 -99.99  24.20 
1982 03 99.99 -99.99  24.90 
1982 04 99.99 -99.99  26.20 
1982 05 99.99 -99.99  25.50 
1982 06 99.99 -99.99  24.50 
1982 07 99.99 -99.99  23.50 
1982 08 99.99 -99.99  25.00 
1982 09 99.99 -99.99  25.00 
1982 10 99.99 -99.99  24.60 
1982 11 99.99 -99.99  23.70 
1982 12 99.99 -99.99  23.20 
1983 01 99.99 -99.99  23.70 
1983 02 99.99 -99.99  24.60 
1983 03 99.99 -99.99  27.10 
1983 04 99.99 -99.99  27.40 
1983 05 99.99 -99.99  28.10 
1983 06 99.99 -99.99  26.10 
1983 07 99.99 -99.99  25.00 
1983 08 99.99 -99.99  24.90 
1983 09 99.99 -99.99  25.10 
1983 10 99.99 -99.99  24.70 
1983 11 99.99 -99.99  24.60 
1983 12 99.99 -99.99  23.20 
1984 01 99.99 -99.99  22.70 
1984 02 99.99 -99.99  23.80 
1984 03 99.99 -99.99  25.40 
1984 04 99.99 -99.99  26.70 
1984 05 99.99 -99.99  26.70 
1984 06 99.99 -99.99  25.30 
1984 07 99.99 -99.99  24.60 
1984 08 99.99 -99.99  24.30 
1984 09 99.99 -99.99  24.20 
1984 10 99.99 -99.99  24.20 
1984 11 99.99 -99.99  22.40 
1984 12 99.99 -99.99  22.80 
1985 01 99.99 -99.99  21.60 
1985 02 99.99 -99.99  23.10 
1985 03 99.99 -99.99  24.40 
1985 04 99.99 -99.99  25.90 
1985 05 99.99 -99.99  25.80 
1985 06 99.99 -99.99  24.70 
1985 07 99.99 -99.99  24.50 
1985 08 99.99 -99.99  24.50 
1985 09 99.99 -99.99  24.60 
1985 10 99.99 -99.99  23.60 
1985 11 99.99 -99.99  23.10 
1985 12 99.99 -99.99  23.20 
1986 01 99.99 -99.99  22.10 
1986 02 99.99 -99.99  23.60 
1986 03 99.99 -99.99  24.20 
1986 04 99.99 -99.99  25.80 
1986 05 99.99 -99.99  26.50 
1986 06 99.99 -99.99  24.50 
1986 07 99.99 -99.99  23.90 
1986 08 99.99 -99.99  24.70 
1986 09 99.99 -99.99  24.50 
1986 10 99.99 -99.99  24.20 
1986 11 99.99 -99.99  24.20 
1986 12 99.99 -99.99  23.80 
1987 01 99.99 -99.99  23.10 
1987 02 99.99 -99.99  24.20 
1987 03 99.99 -99.99  26.30 
1987 04 99.99 -99.99  26.70 
1987 05 99.99 -99.99  26.90 
1987 06 99.99 -99.99  26.40 
1987 07 99.99 -99.99  24.10 
1987 08 99.99 -99.99  25.30 
1987 09 99.99 -99.99  25.50 
1987 10 99.99 -99.99  23.70 
1987 11 99.99 -99.99  23.20 
1987 12 99.99 -99.99  24.90 
1988 01 99.99 -99.99  23.10 
1988 02 99.99 -99.99  23.60 
1988 03 99.99 -99.99  25.10 
1988 04 99.99 -99.99  25.80 
1988 05 99.99 -99.99  25.10 
1988 06 99.99 -99.99  23.60 
1988 07 99.99 -99.99  23.00 
1988 08 99.99 -99.99  23.10 
1988 09 99.99 -99.99  23.50 
1988 10 99.99 -99.99  20.50 
1988 11 99.99 -99.99  22.60 
1988 12 99.99 -99.99  20.90 
1989 01 99.99 -99.99  21.80 
1989 02 99.99 -99.99  21.50 
1989 03 99.99 -99.99  23.50 
1989 04 99.99 -99.99  25.30 
1989 05 99.99 -99.99  25.50 
1989 06 99.99 -99.99  23.50 
1989 07 99.99 -99.99  24.00 
1989 08 99.99 -99.99  25.10 
1989 09 99.99 -99.99  23.30 
1989 10 99.99 -99.99  23.30 
1989 11 99.99 -99.99  22.10 
1989 12 99.99 -99.99  21.60 
1990 01 99.99 -99.99  22.30 
1990 02 99.99 -99.99  22.80 
1990 03 99.99 -99.99  24.40 
1990 04 99.99 -99.99  25.30 
1990 05 99.99 -99.99  24.20 
1990 06 99.99 -99.99  25.00 
1990 07 99.99 -99.99  24.50 
1990 08 99.99 -99.99  24.20 
1990 09 99.99 -99.99  23.80 
1990 10 99.99 -99.99  23.90 
1990 11 99.99 -99.99  22.80 
1990 12 99.99 -99.99  22.50 
