How reliable is the mail delivery? Do you know how much mail is lost? One percent, more, less? (I believe one kind of failure is called UAA - undeliverable as addressed.)

I'd love to learn more, but don't know where to start.

Some of us election integrity activists are deeply concerned with the transition to vote by mail (all postal ballots, no more poll sites). One practical complaint is our assumption that 1% of all mail is lost. In a big county like mine, that's 12,000 ballots.

My FOIA requests were rebuffed. Apparently the data gathering is done by third parties, so is considered proprietary. (A nice dodge, illustrating how privatization reduces government transparency and accountability.)

The best information I found was looking at court cases, where USPS' customers (eg bulk mailers) dispute the UAA, and don't want to pay extra.