| MONTH | PERIOD ANALYZED IN CHB | |||||||
| 1961-1979 | 1979-1998 | 1998-2015 | 1961-2015 | |||||
| DEF | EXC | DEF | EXC | DEF | EXC | DEF | EXC | |
| JANUARY | 0.0 | 159.0 | 0.0 | 182.6 | 0.0 | 181.0 | 0.0 | 179.7 |
| FEBRUARY | 0.0 | 111.5 | 0.0 | 109.1 | 0.0 | 104.4 | 0.0 | 109.0 |
| MARCH | 0.0 | 63.8 | 0.0 | 117.6 | 0.0 | 70.3 | 0.0 | 84.2 |
| APRIL | −0.1 | 0.0 | 0.0 | 6.5 | −0.3 | 0.0 | 0.0 | 0.0 |
| MAY | −0.1 | 0.0 | 0.0 | 11.3 | −0.3 | 0.0 | 0.0 | 0.0 |
| JUNE | −1.6 | 0.0 | −0.7 | 0.0 | −3.6 | 0.0 | −1.1 | 0.0 |
| JULY | −1.8 | 0.0 | −3.8 | 0.0 | −6.9 | 0.0 | -3.3 | 0.0 |
| AUGUST | −8.0 | 0.0 | −14.3 | 0.0 | −16.7 | 0.0 | −11.6 | 0.0 |
| SEPTEMBER | −3.7 | 0.0 | 0.0 | 0.0 | −3.6 | 0.0 | 0.0 | 0.0 |
| OCTOBER | 0.0 | 20.4 | 0.0 | 20.1 | 0.0 | 0.0 | 0.0 | 0.0 |
| NOVEMBER | 0.0 | 107.6 | 0.0 | 81.8 | 0.0 | 11.4 | 0.0 | 82.3 |
| DECEMBER | 0.0 | 172.2 | 0.0 | 210.0 | 0.0 | 131.2 | 0.0 | 165.4 |