| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
1 | | | | | | | 23.0 | 27.5 | 24.4 | 16.0 | 14.3 | 5.4 |
2 | | | | | | | 24.9 | 27.8 | 22.9 | 18.3 | 17.0 | 6.3 |
3 | | | | | | | 26.6 | 27.9 | 20.5 | 19.1 | 16.5 | 9.9 |
4 | | | | | | | 25.9 | 28.4 | 23.0 | 18.3 | 17.2 | 10.1 |
5 | | | | | | | 25.4 | 27.2 | 23.8 | 17.7 | 14.1 | 10.7 |
6 | | | | | | | 26.8 | 28.0 | 23.1 | 17.2 | 11.0 | 7.9 |
7 | | | | | | | 26.4 | 29.5 | 24.8 | 17.7 | 12.5 | 9.1 |
8 | | | | | | | 25.6 | 27.1 | 24.9 | 16.3 | 14.8 | 9.2 |
9 | | | | | | | 23.9 | 27.2 | 24.3 | 17.6 | 17.6 | 12.1 |
10 | | | | | | | 24.3 | 26.2 | 24.5 | 19.0 | 16.4 | 11.1 |
11 | | | | | | | 24.3 | | 22.0 | 18.6 | 14.8 | 7.6 |
12 | | | | | | | 25.2 | | 22.0 | 17.8 | 10.0 | 2.8 |
13 | | | | | | | 26.7 | 29.4 | 21.2 | 18.1 | 12.8 | 6.2 |
14 | | | | | | | 26.2 | 23.6 | 23.2 | 16.7 | 13.7 | 7.6 |
15 | | | | | | | 25.2 | 25.5 | 25.1 | 17.2 | 11.4 | 10.5 |
16 | | | | | | | 26.1 | 25.7 | 23.9 | 18.2 | 13.2 | 12.3 |
17 | | | | | | | 27.4 | 24.5 | 21.3 | 18.1 | 13.4 | 10.5 |
18 | | | | | | | 29.6 | 23.9 | 16.8 | 17.2 | 15.3 | 7.8 |
19 | | | | | | | 29.8 | 21.9 | 18.9 | 17.0 | 12.1 | 8.6 |
20 | | | | | | | 29.1 | 18.3 | 18.8 | 17.4 | 11.0 | 11.0 |
21 | | | | | | | 27.2 | 18.8 | 18.5 | 17.6 | 10.2 | 11.4 |
22 | | | | | | | 27.2 | 26.3 | 16.3 | 21.2 | 10.4 | 11.9 |
23 | | | | | | | 27.0 | 19.3 | 15.5 | 21.8 | 7.7 | 11.8 |
24 | | | | | | | 29.6 | 24.2 | 15.1 | 22.1 | 8.1 | 13.9 |
25 | | | | | | | 29.6 | 24.9 | 18.2 | 21.4 | 9.5 | 14.3 |
26 | | | | | | | 26.5 | | 17.1 | 18.8 | 12.4 | 14.5 |
27 | | | | | | 19.7 | 27.9 | | 17.6 | 17.8 | 8.3 | 14.1 |
28 | | | | | | 24.2 | 26.3 | | 17.4 | 15.9 | 6.6 | 11.2 |
29 | | | | | | 22.7 | 25.2 | | 19.5 | 18.5 | 9.0 | 13.9 |
30 | | | | | | 18.3 | 26.0 | 20.3 | 15.1 | 15.4 | 8.7 | 14.0 |
31 | | | | | | | 26.2 | 23.4 | | 14.7 | | 13.1 |