No, mine's been steadily increasing over the past months. Some of them make themselves easy to delete by either using timestamps from 1900, or else 6 copies of the same thing come in.
Spamming should at the very least be punishable by Zapp Brannigan's sentence of 5 concurrent death sentences.
I don't use filters, because I don't like the risk of false positives. And if I have to search the junk folder for any false positives to save, that kind of defeats the purpose of having a spam filter in the first place.