| Category | Frequency per million words |
| Unpublished written material | 250.75 |
| Newspapers | 105.18 |
| Other published written material | 70.13 |
| Fiction and verse | 62.93 |
| Other spoken material | 53.6 |
| Non-academic prose and biography | 37.35 |
| Academic prose | 34.61 |
| Spoken conversation | 31.89 |
| Total | 64.06 |