Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Mountain West | Lost | Tied | Pct. | Years | Total Games |
| --- | --- | --- | --- | --- | --- |
| Boise State | 148.0 | 2.0 | 0.723 | 45.0 | 538.0 |
| Fresno State | 388.0 | 27.0 | 0.5907 | 91.0 | 981.0 |
| Hawaii | 397.0 | 24.0 | 0.5635 | 96.0 | 945.0 |
| San Diego State | 398.0 | 32.0 | 0.5553 | 90.0 | 931.0 |
| Air Force | 291.0 | 13.0 | 0.5451 | 57.0 | 654.0 |
| Nevada | 447.0 | 33.0 | 0.5351 | 106.0 | 997.0 |
| San Jose State | 461.0 | 38.0 | 0.5016 | 95.0 | 963.0 |
| Utah State | 505.0 | 31.0 | 0.4961 | 115.0 | 1033.0 |
| Wyoming | 532.0 | 28.0 | 0.4844 | 116.0 | 1059.0 |
| Colorado State | 544.0 | 33.0 | 0.4702 | 114.0 | 1058.0 |
| New Mexico | 553.0 | 31.0 | 0.4539 | 114.0 | 1041.0 |
| UNLV | 301.0 | 4.0 | 0.4434 | 45.0 | 512.0 |
| TOTAL | 4959.0 | 296.0 | 0.522 | 90.3 | 10687.0 |
Question:
How many years for the team with under 31 ties and a percentage of 0.5451?
Answer:
57.0