| Time Period | Unlimited License Mariners | Unlicensed Mariners |
|---|---|---|
| 4 years or less | 34% | 24% |
| 5-9 years | 23% | 18% |
| 10-14 years | 19% | 19% |
| 15-19 years | 11% | 14% |
| 20 or more years | 14% | 25% |
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics and Maritime Administration, 2002 Mariner Survey, Principal Findings, Washington, DC.