| in the united states | 6 | location |
| due to widespread immunization | 3 | cause |
| very | 2 | degree |
| rubella → be → rare | 5 |
| rubella → be → uncommon | 5 |
| negative | neutral | positive |
| 0.290 | 0.595 | 0.116 |
| Raw frequency | 10 |
| Normalized frequency | 0.425 |
| Modifier score | 0.500 |
| Perplexity | 82.088 |