| Definition: | Percentage of fields in each county which are associated gas, listed in 10% intervals and color coded on the map. |
| Color coded in shades of blue. | |
| 0% - 10% | |
| 11% - 20% | |
| 21% - 30% | |
| 31% - 40% | |
| 41% - 50% | |
| 51% - 60% | |
| 61% - 70% | |
| 71% - 80% | |
| 81% - 90% | |
| 91% - 100% |