| unknown number | 37.99 | An unknown number died waiting. | ||
| unknown assailant | 19.35 | Holland was shot dead by unknown assailants Friday night. | ||
| unknown reason | 14.29 | But he did not enter for unknown reasons. | ||
| unknown group | 12.11 | A previously unknown group claimed responsibility. | ||
| unknown gunman | 8.89 | They were shot by an unknown gunman. | ||
| unknown destination | 7.70 | He was then taken to an unknown destination. | ||
| unknown quantity | 7.18 | It is an unknown quantity. | ||
| unknown attacker | 5.73 | The unknown attacker escaped, it said. | ||
| unknown location | 4.81 | Some were taken to unknown locations. | ||
| unknown origin | 4.48 | Ebola is a usually fatal virus of unknown origin. | ||
| unknown factor | 4.15 | He is the unknown factor. | ||
| unknown man | 2.90 | But the Samaritan stopped to care for the unknown man. | ||
| unknown amount | 2.44 | The delay will cost taxpayers an unknown amount of money, he said. | ||
| unknown territory | 2.37 | But she walked into unknown territory. | ||
| unknown person | 2.30 | The DNA belongs to an unknown person, possibly the killer. | ||
| unknown cause | 2.17 | He died of unknown causes. | ||
| unknown source | 2.04 | Refuse politely any cold drink from an unknown source. | ||
| unknown actor | 1.65 | The play had a cast of almost unknown actors. | ||
| unknown people | 1.38 | Unknown people then opened fire. | ||
| unknown species | 1.38 | Even entirely unknown species turn up. |