| to burn coal | 16 | purpose |
| at a rate | 5 | manner |
| since the late 1800s | 3 | temporal |
| human → burn → gas | 22 |
| human → burn → natural gas | 20 |
| negative | neutral | positive |
| 0.575 | 0.399 | 0.027 |
| Raw frequency | 42 |
| Normalized frequency | 0.522 |
| Modifier score | 0.900 |
| Perplexity | 129.928 |