As a heavily unionized, quasi-government agency, it's no surprise that the United States Postal Service has a big focus on equal employment opportunities for both men and women.
"There is far more transparency about wages in the public sector and are there are not penalties for discussing salary," said Fatima Goss Graves, vice president of education and employment for the National Women's Law Center.
Full-time women postal clerks made about $52,601 in 2011, 98 cents to the dollar of their male coworkers. That's according to a CNNMoney analysis of Census data.
A pay gap that small is likely explained by some men working slightly longer hours.
But postal workers don't exactly enjoy job security these days.
Source: American Community Survey 2011. We included occupations with at least 20,000 full-time workers, where women make a median annual salary that's equal to at least 90% of a man's full-time salary. We only included fields where women don't outnumber men, and men don't outnumber women, by more than 20%.