Site Selection for the 1981 Worldcon was held at Seacon 79, the 1979 Worldcon held in Brighton, UK. It is unclear if Seacon 79 ever published minutes of the WSFS Business Meeting with full site selection totals, but some numbers do exist.
The results were:
|At Site||1st Totals||Final Total|
|Denver in '81||275||174||449||453|
|Seattle in 1981||172||148||320||320|
|LA in '81||85||44||129||130|
|Needed to win||460||452|
The "Final Total" column is puzzling, since the Denver in '81 and LA in '81 vote counts went up compared with "First Totals", but all that is shown as having been eliminated (Unpaid, Invalid and No Preference) which should not have changed the remaining counts. It it common for there to be a few ballots listing written in hoax bids first, and they will normally have a real bid as a second choice. So it seems likely that they were left off the report, but that it was their second choices whichjust brought Denver in '81 up to a majority giving it a first-ballot win.
The Seattle in 1981 bid committee reportedly had about 20 hand-carried votes which were not counted. Had they been counted, this would not have affected the final result, but would have forced one more elimination round during vote counting.