Customer Service
800-331-3332 or 312-930-2316

|
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
Yearly |
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1980 | 30.5 | 11.9 | 9.5 | 14.9 | 16.7 | 9.2 | 43.0 | 25.7 | 26.2 | 28.2 | 30.2 | 41.5 |
24.0 |
| 1981 | 30.6 | 27.5 | 17.9 | 23.5 | 18.5 | 15.0 | 20.5 | 19.0 | 14.2 | 8.0 | 12.8 | 18.8 |
18.9 |
| 1982 | 14.5 | 9.4 | 15.1 | 15.8 | 8.9 | 15.3 | 12.0 | 18.4 | 11.1 | 17.6 | 18.3 | 15.2 |
14.3 |
| 1983 | 15.5 | 13.8 | 19.6 | 14.1 | 13.6 | 24.7 | 28.7 | 47.4 | 44.3 | 34.0 | 25.9 | 31.2 |
26.1 |
| 1984 | 33.0 | 20.7 | 14.5 | 22.5 | 23.8 | 25.3 | 27.0 | 28.0 | 21.5 | 19.9 | 12.3 | 19.5 |
22.3 |
| 1985 | 16.1 | 19.1 | 20.1 | 12.9 | 15.6 | 19.5 | 31.2 | 14.6 | 20.5 | 17.0 | 23.0 | 24.5 |
19.5 |
| 1986 | 22.8 | 15.9 | 14.4 | 15.0 | 13.0 | 9.1 | 10.7 | 16.7 | 10.4 | 11.7 | 6.3 | 9.7 |
13.0 |
| 1987 | 12.0 | 10.7 | 12.4 | 15.3 | 38.2 | 38.8 | 220 | 11.8 | 22.2 | 23.5 | 25.7 | 23.5 |
21.3 |
| 1988 | 22.6 | 22.8 | 16.2 | 14.1 | 30.9 | 55.2 | 29.5 | 34.1 | 25.8 | 25.6 | 27.6 | 19.2 |
29.4 |
| 1989 | 26.4 | 21.0 | 23.4 | 16.4 | 17.9 | 25.7 | 34.6 | 21.0 | 15.0 | 13.8 | 11.9 | 10.3 |
19.8 |
| 1990 | 9.3 | 8.8 | 18.8 | 23.3 | 19.3 | 17.5 | 24.5 | 16.5 | 19.7 | 23.6 | 20.5 | 18.4 |
18.3 |
| 1991 | 19.2 | 13.1 | 18.7 | 23.2 | 8.2 | 20.9 | 30.3 | 42.4 | 18.2 | 18.9 | 15.2 | 15.8 |
20.4 |
| 1992 | 14.9 | 12.0 | 10.8 | 10.5 | 21.7 | 17.7 | 9.8 | 12.6 | 10.5 | 8.0 | 13.3 | 9.0 |
12.6 |
| 1993 | 6.9 | 7.0 | 7.9 | 7.6 | 8.8 | 20.3 | 26.9 | 17.4 | 18.4 | 12.2 | 22.5 | 9.9 |
13.8 |
| 1994 | 11.8 | 9.3 | 12.8 | 18.3 | 34.0 | 27.8 | 17.7 | 11.5 | 10.7 | 11.5 | 8.1 | 17.1 |
15.8 |
| 1995 | 10.9 | 10.1 | 13.8 | 16.1 | 16.1 | 20.2 | 26.0 | 14.3 | 24.7 | 12.7 | 12.7 | 18.7 |
17.2 |
| 1996 | 17.7 | 16.1 | 18.1 | 27.9 | 18.9 | 21.8 | 22.0 | 13.4 | 20.4 | 21.7 | 17.1 | 16.3 |
19.3 |
| 1997 | 18.5 | 22.0 | 28.4 | 29.0 | 21.7 | 26.4 | 27.5 | 24.0 | 25.7 | 27.1 | 30.4 | 19.0 |
25.0 |
| 1998 | 19.3 | 13.1 | 18.8 | 21.7 | 20.9 | 41.4 | 30.1 | 16.1 | 18.7 | 34.4 | 24.9 | 17.0 |
23.0 |
| 1999 | 17.0 | 22.6 | 22.2 | 18.0 | 17.1 | 19.9 | 42.9 | 36.4 | 28.8 | 21.7 | 22.2 | 17.2 |
23.8 |
| 2000 | 21.2 | 24.2 | 20.0 | 19.6 | 23.3 | 16.9 | 14.4 | 15.2 | 21.3 | 19.5 | 26.1 | 12.0 |
19.4 |
| 2001 | 16.1 | 17.3 | 21.8 | 21.5 | 23.0 | 21.9 | 24.6 | 20.0 | 24.9 | 17.5 | 17.1 | 15.5 |
20.1 |
| 2002 | 30.6 | 18.6 | 16.2 | 17.3 | 17.2 | 20.6 | 32.6 | 25.3 | 21.0 | 18.8 | 13.9 | 16.6 |
20.7 |
| 2003 | 23.0 | 20.2 | 19.1 | 24.4 | 18.5 | 21.2 | 18.7 | 30.2 | 21.3 | 24.7 | 24.4 | 32.8 |
23.2 |
| 2004 | 28.0 | 28.3 | 25.9 | 36.1 | 49.9 | 36.7 | 37.9 | 38.7 | 15.7 | 25.7 | 25.5 | 23.2 |
31.0 |
| 2005 | 30.3 | 33.2 | 33.3 | 20.8 | 23.7 | 36.5 | 33.1 | 25.1 | 14.7 | 24.2 | 24.8 | 29.2 |
27.4 |
| 2006 | 23.6 | 22.3 | 17.2 | 18.1 | 13.3 | 28.2 | 13.2 | 14.3 | 21.3 | 21.6 | 16.8 | 16.5 |
18.9 |
| 2007 | 33.8 | 15.7 | 20.3 | 15.3 | 22.5 | 32.1 | 43.3 | 25.7 | 23.2 | 33.2 | 20.4 | 22.1 |
25.6 |
| 2008 | 28.4 | 20.9 | 64.9 | 37.6 | 33.2 | 29.5 |
37.0 |
||||||
| Mean | 20.8 | 17.5 | 19.7 | 18.9 | 21.3 | 24.5 | 27.3 | 22.7 | 20.3 | 20.6 | 19.6 | 19.3 |
|
| High | 33.8 | 33.2 | 64.9 | 37.6 | 49.9 | 55.2 | 59.5 | 47.4 | 44.3 | 34.4 | 30.4 | 41.5 |
|
| Low | 6.9 | 7.0 | 7.9 | 7.6 | 8.4 | 9.1 | 9.8 | 11.5 | 10.4 | 8.0 | 6.3 | 9.0 |
|