Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
| 140.4 | 136 | 195 | 199 | 251 | 301 | 283 | 242.1 | 265 | 232.8 | 173.1 | 144.8 |
Mean | 4.53 | 4.69 | 6.29 | 6.63 | 8.09 | 10.03 | 9.13 | 7.81 | 8.83 | 7.51 | 5.77 | 4.67 |
St. Dev | 1.11 | 0.85 | 0.68 | 1.06 | 0.87 | 1.04 | 0.79 | 1.21 | 1.18 | 0.61 | 0.34 | 0.93 |