| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | |||||
| 2008 | 3.8 | 3.2 | 4.4 | 1 | 0.6 | 5.3 | 5.6 | 9.2 | 0.5 | 3.7 | 1.5 | 0.9 |
| 2007 | 4 | 3.2 | 1.7 | 0.7 | 0.8 | 6.9 | 8.9 | 6.6 | 3.4 | 7 | 0.8 | 2 |
| 2006 | 3.4 | 5.1 | 0.3 | 3.5 | 0.6 | 4.8 | 5.5 | 2.8 | 3.1 | 2.6 | 0.9 | 2.8 |
| 2005 | 1.4 | 1.8 | 4.6 | 5.4 | 4.1 | 8.1 | 4.9 | 7.4 | 1.2 | 3.4 | 1.2 | 6.4 |
| 2004 | 1.6 | 5.5 | 2 | 1.1 | 0.5 | 7.1 | 4 | 14.2 | 16.4 | 2.6 | 2 | 1.3 |
| NEUTRAL | EL NIÑO | LA NIÑA |