| Year |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| 1973 |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
| 1974 |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
|
| 1975 |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
| 1976 |
0.54 |
0.54 |
0.54 |
0.55 |
0.55 |
0.58 |
0.58 |
0.60 |
0.60 |
0.62 |
0.63 |
0.64 |
| 1977 |
0.67 |
0.71 |
0.75 |
0.77 |
0.77 |
0.82 |
0.83 |
0.82 |
0.83 |
0.84 |
0.83 |
0.84 |
| 1978 |
0.87 |
0.88 |
0.89 |
0.88 |
0.91 |
0.91 |
0.89 |
0.91 |
0.92 |
0.92 |
0.93 |
0.96 |
| 1979 |
1.02 |
1.05 |
1.10 |
1.11 |
1.15 |
1.17 |
1.20 |
1.24 |
1.24 |
1.28 |
1.29 |
1.31 |
| Year |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
|
| 1980 |
1.37 |
1.42 |
1.46 |
1.51 |
1.56 |
1.57 |
1.64 |
1.64 |
1.69 |
1.71 |
1.76 |
1.74 |
| 1981 |
1.77 |
1.81 |
1.86 |
1.93 |
1.95 |
1.95 |
2.01 |
2.02 |
2.08 |
2.11 |
2.15 |
2.16 |
| 1982 |
2.23 |
2.30 |
2.35 |
2.40 |
2.45 |
2.45 |
2.47 |
2.53 |
2.56 |
2.60 |
2.62 |
2.62 |
| 1983 |
2.66 |
2.66 |
2.58 |
2.53 |
2.53 |
2.59 |
2.52 |
2.58 |
2.67 |
2.58 |
2.60 |
2.61 |
| 1984 |
2.67 |
2.71 |
2.67 |
2.64 |
2.67 |
2.70 |
2.68 |
2.69 |
2.62 |
2.63 |
2.61 |
2.57 |
| Year |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
|
| 1985 |
2.64 |
2.71 |
2.62 |
2.64 |
2.53 |
2.58 |
2.51 |
2.47 |
2.42 |
2.37 |
2.36 |
2.28 |
| 1986 |
2.28 |
2.26 |
2.16 |
2.10 |
1.96 |
1.85 |
1.80 |
1.77 |
1.78 |
1.73 |
1.77 |
1.76 |
| 1987 |
1.74 |
1.73 |
1.73 |
1.69 |
1.65 |
1.65 |
1.66 |
1.63 |
1.56 |
1.57 |
1.64 |
1.70 |
| 1988 |
1.96 |
1.84 |
1.70 |
1.59 |
1.52 |
1.53 |
1.56 |
1.62 |
1.53 |
1.68 |
1.76 |
1.89 |
| 1989 |
1.99 |
1.81 |
1.69 |
1.56 |
1.61 |
1.65 |
1.65 |
1.61 |
1.55 |
1.58 |
1.66 |
1.92 |
| Year |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
|
| 1990 |
2.23 |
1.85 |
1.55 |
1.49 |
1.47 |
1.48 |
1.49 |
1.51 |
1.56 |
1.76 |
1.94 |
2.04 |
| 1991 |
1.96 |
1.62 |
1.49 |
1.50 |
1.48 |
1.43 |
1.34 |
1.43 |
1.59 |
1.82 |
1.89 |
2.00 |
| 1992 |
1.74 |
1.26 |
1.35 |
1.42 |
1.51 |
1.62 |
1.55 |
1.84 |
1.92 |
2.38 |
2.13 |
2.07 |
| 1993 |
2.03 |
1.76 |
2.00 |
2.06 |
2.18 |
1.98 |
1.99 |
2.04 |
2.09 |
2.02 |
2.03 |
2.15 |
| 1994 |
1.93 |
1.88 |
1.93 |
1.91 |
2.00 |
1.80 |
1.81 |
1.83 |
1.78 |
1.70 |
1.75 |
1.88 |
| Year |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
|
| 1995 |
1.62 |
1.48 |
1.47 |
1.52 |
1.55 |
1.58 |
1.43 |
1.43 |
1.52 |
1.54 |
1.61 |
1.84 |
| 1996 |
2.05 |
1.89 |
1.95 |
2.08 |
2.01 |
2.08 |
2.25 |
2.10 |
1.85 |
1.94 |
2.50 |
3.26 |
| 1997 |
3.40 |
2.49 |
1.79 |
1.81 |
2.00 |
2.08 |
2.00 |
2.08 |
2.33 |
2.68 |
2.92 |
2.28 |
| 1998 |
1.96 |
1.96 |
2.06 |
2.16 |
2.04 |
1.91 |
2.09 |
1.82 |
1.70 |
1.86 |
1.94 |
1.95 |
| 1999 |
1.85 |
1.77 |
1.70 |
1.90 |
2.17 |
2.14 |
2.20 |
2.51 |
2.62 |
2.52 |
2.68 |
2.24 |
| Year |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
|
| 2000 |
2.60 |
2.73 |
2.66 |
2.86 |
3.04 |
3.77 |
3.84 |
3.73 |
4.26 |
4.58 |
4.40 |
5.77 |
| 2001 |
6.82 |
5.08 |
4.37 |
4.52 |
4.36 |
3.79 |
3.35 |
3.33 |
2.93 |
2.78 |
3.41 |
3.42 |
| 2002 |
2.50 |
2.19 |
2.40 |
2.94 |
2.94 |
2.96 |
2.92 |
2.76 |
2.97 |
3.24 |
3.59 |
3.96 |
| 2003 |
4.43 |
5.05 |
6.96 |
4.47 |
4.77 |
5.41 |
5.08 |
4.46 |
4.59 |
4.32 |
4.26 |
4.76 |
| 2004 |
5.53 |
5.15 |
4.97 |
5.20 |
5.63 |
5.85 |
5.60 |
5.36 |
4.86 |
5.45 |
6.07 |
6.25 |