CDN lists theses every other week. Look at the BU roll prices and divide by the number of coins in the roll. Then there will be mint set listings every week. In almost every case the set is worth more busted up than it is intact.
It's a strange situation since these are the nicest coins out there and there aren't any of some of the BU rolls anyway. It really doesn't figure but is probably reflective of the fact that many people want singles and don't want to destroy their mint sets.
With the huge destruction taking place there might come a time that the sets get a big premium. Consider that if this day ever comes the coins will have to sell for far higher prices than currently since the mint sets are the sole source for so many of them.
Time don't fly, it bounds and leaps.