| Jan | Feb | March | April | May | June | July | Aug | Sept | Oct | Nov | Dec |
1 | 13.4 | 16.8 | | | | | | | | | | |
2 | 13.9 | 17.3 | | | | | | | | | | |
3 | 13.0 | 14.2 | | | | | | | | | | |
4 | 11.5 | 13.2 | | | | | | | | | | |
5 | 9.0 | 14.9 | | | | | | | | | | |
6 | 10.4 | 15.8 | | | | | | | | | | |
7 | 13.5 | 9.8 | | | | | | | | | | |
8 | 10.5 | 7.8 | | | | | | | | | | |
9 | 11.7 | 15.8 | | | | | | | | | | |
10 | 11.0 | 16.5 | | | | | | | | | | |
11 | 10.0 | 15.3 | | | | | | | | | | |
12 | 10.7 | | | | | | | | | | | |
13 | 12.1 | | | | | | | | | | | |
14 | 12.9 | | | | | | | | | | | |
15 | 13.5 | | | | | | | | | | | |
16 | 13.6 | | | | | | | | | | | |
17 | 13.9 | | | | | | | | | | | |
18 | 12.1 | | | | | | | | | | | |
19 | 12.0 | | | | | | | | | | | |
20 | 11.6 | | | | | | | | | | | |
21 | 11.8 | | | | | | | | | | | |
22 | 14.8 | | | | | | | | | | | |
23 | 15.7 | | | | | | | | | | | |
24 | 15.5 | | | | | | | | | | | |
25 | 15.1 | | | | | | | | | | | |
26 | 19.3 | | | | | | | | | | | |
27 | 16.4 | | | | | | | | | | | |
28 | 11.1 | | | | | | | | | | | |
29 | 12.1 | | | | | | | | | | | |
30 | 13.4 | | | | | | | | | | | |
31 | 17.5 | | | | | | | | | | | |
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