| Keyword | CPC | PCC | Volume | Score | Length of keyword |
|---|---|---|---|---|---|
| oxygen levels over time | 1.16 | 0.4 | 1999 | 32 | 23 |
| oxygen | 0.41 | 0.1 | 7850 | 15 | 6 |
| levels | 1.58 | 0.8 | 2015 | 80 | 6 |
| over | 0.88 | 0.8 | 6585 | 82 | 4 |
| time | 0.51 | 0.2 | 7173 | 40 | 4 |
| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| oxygen levels over time | 1.17 | 0.4 | 6386 | 91 |
| atmospheric oxygen levels over time | 1.59 | 0.2 | 1015 | 15 |
| oxygen levels in atmosphere over time | 1.41 | 0.1 | 5729 | 55 |
| oxygen levels on earth over time | 0.44 | 0.9 | 5844 | 87 |
| oxygen levels on earth over time graph | 1 | 0.6 | 2290 | 31 |
| how have oxygen levels changed over time | 0.09 | 0.9 | 6714 | 89 |
| oxygen levels over geological time | 1.52 | 0.4 | 9966 | 32 |
| earth oxygen level over time | 0.39 | 0.4 | 2282 | 58 |
| oxygen levels in the atmosphere | 0.87 | 0.5 | 8194 | 14 |
| rise in atmospheric oxygen | 1.31 | 0.6 | 9536 | 54 |
| normal atmospheric oxygen levels | 1.57 | 0.1 | 84 | 23 |
| oxygen approximate level in the atmosphere | 0.92 | 1 | 5138 | 37 |
| increased levels of oxygen in the atmosphere | 0.31 | 0.9 | 1121 | 5 |
| oxygen levels going up and down | 0.28 | 0.5 | 9821 | 82 |
| current oxygen levels in atmosphere | 1 | 0.8 | 1360 | 86 |
| percentage of oxygen in early atmosphere | 1.41 | 0.7 | 7861 | 83 |
| normal oxygen levels in atmosphere | 0.02 | 1 | 9316 | 46 |
| normal oxygen atmosphere level | 1.66 | 0.2 | 1245 | 8 |
| oxygen level in the air | 1.63 | 0.5 | 8669 | 13 |
