| Keyword | CPC | PCC | Volume | Score | Length of keyword |
|---|---|---|---|---|---|
| when was chemical warfare introduced | 0.04 | 0.7 | 6878 | 29 | 36 |
| when | 1.41 | 1 | 8536 | 71 | 4 |
| was | 0.36 | 0.5 | 9589 | 83 | 3 |
| chemical | 0.99 | 0.6 | 4517 | 10 | 8 |
| warfare | 0.61 | 1 | 2694 | 5 | 7 |
| introduced | 1.41 | 0.4 | 8907 | 1 | 10 |
| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| when was chemical warfare introduced | 1.34 | 0.4 | 3531 | 49 |
