I don't know but my Brother is a postal carrier and he's told me that the last two-three weeks have been bizzare.
He said the last few days in particular he's received nothing to deliver except campaign flyers.
Typically he has around quarter tub (the square, hard plastic postal boxes you see in businesses) of first class mail. This would be all non-junk mail...bills, statements, small packet meds, etc. and he typically has 75-100 packages to deliver.
Monday he said he had zero first class mail and 10 packages. Being closed on Sunday typically makes Monday the largest package day and he often has 125+.
He and all his co-workers are expecting a mountain of "held" mail to come in from the processing facility this week.