| 1983 | 1987 | 1991 | |
| Men | |||
| Total, 25 years and older | 6.4 | 6.2 | 5.9 |
| Less than 4 years of high school | 7.3 | 6.1 | 5.5 |
| 4 years of high school | 7.3 | 6.5 | 6.1 |
| 1 to 3 years of college | 5.5 | 5.9 | 5.7 |
| 4 years or more of college | 5.5 | 6.0 | 6.0 |
| Women | |||
| Total, 25 years and older | 4.7 | 4.8 | 4.8 |
| Less than 4 years of high school | 5.4 | 4.6 | 4.1 |
| 4 years of high school | 5.1 | 5.2 | 5.0 |
| 1 to 3 years of college | 4.0 | 4.3 | 4.6 |
| 4 years or more of college | 4.3 | 4.7 | 4.8 |
| RETURN | |||