That means that the only jobs available are those where people have moved on to a better job, or where they've retired.
Men and women have different expectations regarding how long they should futz around with a potential employer before they're hired. There are books written about the phenomenon, and I know it's always going to be a surprise to some, but men and women are different.
So, who are the women who wait around for a postal opening? Well, for starters, they are ladies who can work nights. About half the workforce shows up after 5 PM, and works to the wee hours of the morning. The other half show up about 4 AM to case mail (they're called letter carriers) and then hit the streets.
A woman with young children will probably not find a postal job compatible with her schedule, but a woman with teenagers will! Besides, with college tuition coming up, and the need for better medical insurance, USPS fits the bill ~ provided there are no young children at home.
Men all too often think postal schedules are a POS. I agree. Still, maintenance has to be done in off-hours (2AM to 10 AM for example).
My own area (Mail Classifiation) had a normal work cycle that fit in perfectly with musicians. At least 1/3 of the people I worked with were, or had been, professional or semi-professional musicians at some time in their working lives, and many continued to leave the Mail Acceptance Units at 9PM and go to the clubs to perform until 1 or 2 AM.
Alas, that wasn't all that large an employment category (350 people in supervisory and specialist positions, and maybe 3400 in clerical levels).
There were other matches like that where people could balance two jobs for a long period of time. Good way to be a high earner too.
There's also a division within the USPS between large facilities and small facilities. About half the workforce work at large facilities and half don't. With the movement of mail processing and the use of heavy machinery to Mail Processing Centers with thousands of employees, there's a tendency for men to show up in MPCs and women to show up in smaller retail, finance and delivery units.
About 20 years ago folks holding greencards as authorized immigrants were allowed to take US government jobs. That's why you see the Asian and Latino ladies at the post office. With the background check performed by Postal Inspectors on every aspiring employee, I doubt there are any illegals in the bunch.
Now, another factor in USPS employment, if you've been convicted of a felony the odds on you getting a job are between ZERO and NONE. Right there is a difference between men and women with women holding an edge in the employment race. Still, I think the ratio by sex is pretty much what it's been for the last 75 years ~ that is, 50/50 with some variation in different place.
Uh huh, sure.