1988 01 99.99 -99.99  28.80 
1988 02 99.99 -99.99  27.50 
1988 03 99.99 -99.99  28.40 
1988 04 99.99 -99.99  27.40 
1988 06 99.99 -99.99  21.70 
1988 07 99.99 -99.99  21.40 
1988 08 99.99 -99.99  23.70 
1988 09 99.99 -99.99  20.10 
1988 10 99.99 -99.99  23.50 
1988 11 99.99 -99.99  26.50 
1988 12 99.99 -99.99  28.40 
1989 01 99.99 -99.99  27.60 
1989 02 99.99 -99.99  28.00 
1989 03 99.99 -99.99  27.20 
1989 04 99.99 -99.99  25.80 
1989 05 99.99 -99.99  20.50 
1989 06 99.99 -99.99  21.00 
1989 07 99.99 -99.99  16.90 
1989 10 99.99 -99.99  20.10 
1989 11 99.99 -99.99  24.00 
1989 12 99.99 -99.99  26.60 
1990 01 99.99 -99.99  27.10 
1990 02 99.99 -99.99  25.50 
1990 03 99.99 -99.99  27.00 
1990 04 99.99 -99.99  27.00 
1990 05 99.99 -99.99  20.10 
1990 06 99.99 -99.99  17.79 
1990 07 99.99 -99.99  12.10 
1990 08 99.99 -99.99  20.40 
1990 09 99.99 -99.99  15.90 
1990 10 99.99 -99.99  25.20 
1990 11 99.99 -99.99  26.00 
1990 12 99.99 -99.99  25.30 
1991 01 99.99 -99.99  27.80 
1991 02 99.99 -99.99  27.40 
1991 03 99.99 -99.99  25.90 
1991 04 99.99 -99.99  22.80 
1991 05 99.99 -99.99  19.90 
1991 06 99.99 -99.99  20.80 
1991 07 99.99 -99.99  16.90 
1991 08 99.99 -99.99  16.10 
1991 09 99.99 -99.99  26.90 
1991 10 99.99 -99.99  24.30 
1991 12 99.99 -99.99  27.70 
1992 01 99.99 -99.99  28.60 
1992 03 99.99 -99.99  27.80 
1992 04 99.99 -99.99  26.60 
1992 05 99.99 -99.99  24.80 
1992 06 99.99 -99.99  22.70 
1992 07 99.99 -99.99   1.00 
1992 08 99.99 -99.99  19.10 
1992 10 99.99 -99.99  26.60 
1992 12 99.99 -99.99  26.20 
1993 01 99.99 -99.99  26.90 
1993 02 99.99 -99.99   2.60 
1993 03 99.99 -99.99  27.00 
1993 04 99.99 -99.99  21.40 
1993 07 99.99 -99.99  20.50 
1993 08 99.99 -99.99  17.29 
1993 09 99.99 -99.99  24.30 
1993 10 99.99 -99.99  29.80 
1993 12 99.99 -99.99  26.60 
1994 01 99.99 -99.99  26.60 
1994 02 99.99 -99.99  25.80 
1994 07 99.99 -99.99  28.70 
1994 08 99.99 -99.99  21.00 
1994 09 99.99 -99.99  26.30 
1994 10 99.99 -99.99  22.80 
1994 11 99.99 -99.99  25.80 
1994 12 99.99 -99.99  25.80 
1995 01 99.99 -99.99  25.80 
1995 03 99.99 -99.99  21.00 
1995 04 99.99 -99.99  25.80 
1995 05 99.99 -99.99  21.00 
1995 06 99.99 -99.99  22.80 
1995 07 99.99 -99.99  19.50 
1995 08 99.99 -99.99  22.80 
1995 10 99.99 -99.99  23.50 
1995 11 99.99 -99.99  25.80 
1996 01 99.99 -99.99  25.80 
1996 02 99.99 -99.99  25.80 
1996 05 99.99 -99.99  22.80 
1996 06 99.99 -99.99  21.00 
1996 08 99.99 -99.99  22.80 
1996 09 99.99 -99.99  22.70 
1996 10 99.99 -99.99  22.70 
1996 11 99.99 -99.99  22.80 
