| Period | Index | Previous Year | Previous Month |
|---|---|---|---|
| December, 1991 | 63.5 | 0.0% | 0.2% |
| November, 1991 | 63.4 | 0.0% | 0.3% |
| October, 1991 | 63.2 | 0.0% | 1.6% |
| September, 1991 | 62.2 | 0.0% | 0.0% |
| August, 1991 | 62.2 | 0.0% | 0.0% |
| July, 1991 | 62.2 | 0.0% | 1.1% |
| June, 1991 | 61.5 | 0.0% | 0.7% |
| May, 1991 | 61.1 | 0.0% | 0.2% |
| April, 1991 | 61.0 | 0.0% | 0.3% |
| March, 1991 | 60.8 | 0.0% | 0.0% |