| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
1 | 11.4 | 7.0 | 12.0 | 14.1 | 15.4 | | | | | | | |
2 | 9.4 | 7.0 | 12.1 | 14.5 | 13.3 | | | | | | | |
3 | 13.8 | 7.7 | 11.8 | 12.8 | 13.0 | | | | | | | |
4 | 12.7 | 10.7 | 10.4 | 13.5 | 15.1 | | | | | | | |
5 | 12.2 | 10.5 | 11.0 | 12.8 | 15.1 | | | | | | | |
6 | 11.5 | 12.0 | 10.0 | 14.1 | | | | | | | | |
7 | 10.0 | 11.7 | 8.0 | 14.1 | | | | | | | | |
8 | 9.9 | 12.0 | 8.5 | 15.3 | | | | | | | | |
9 | 7.4 | 13.1 | 11.7 | 14.5 | | | | | | | | |
10 | 5.7 | 12.1 | 11.9 | 14.0 | | | | | | | | |
11 | 6.7 | 11.7 | 10.3 | 15.6 | | | | | | | | |
12 | 4.1 | 9.3 | 10.0 | 16.6 | | | | | | | | |
13 | 4.7 | 8.8 | 10.6 | 18.3 | | | | | | | | |
14 | 8.8 | 8.4 | 10.2 | 17.9 | | | | | | | | |
15 | 8.8 | 8.1 | 11.1 | 16.7 | | | | | | | | |
16 | 8.1 | 9.9 | 13.3 | 16.4 | | | | | | | | |
17 | 12.2 | 10.8 | 11.7 | 14.1 | | | | | | | | |
18 | 14.5 | 9.7 | 11.5 | 9.8 | | | | | | | | |
19 | 12.7 | 10.4 | 13.6 | 12.4 | | | | | | | | |
20 | 7.2 | 10.3 | 13.0 | 13.1 | | | | | | | | |
21 | 2.7 | 9.1 | 12.2 | 10.5 | | | | | | | | |
22 | 4.6 | 11.0 | 13.4 | 8.6 | | | | | | | | |
23 | 10.9 | 12.1 | 11.9 | 8.3 | | | | | | | | |
24 | 6.3 | 8.3 | 12.7 | 9.5 | | | | | | | | |
25 | 9.4 | 8.7 | 10.9 | 10.2 | | | | | | | | |
26 | 10.9 | 8.6 | 12.5 | 11.9 | | | | | | | | |
27 | 10.1 | 10.4 | 11.8 | 14.6 | | | | | | | | |
28 | 7.7 | 13.7 | 14.2 | 16.8 | | | | | | | | |
29 | 6.0 | 16.5 | 15.6 | 19.7 | | | | | | | | |
30 | 5.6 | | 14.9 | 19.8 | | | | | | | | |
31 | 6.9 | | 15.2 | | | | | | | | | |