I was looking at this year's Hugo voting report (PDF) just now, and was surprised at the number of nomination ties in the fiction categories. (See pp. 18-19 of that report.)
Background: In a year with no ties, there are twenty prose fiction works on the ballot, five works in each of the four fiction categories. But if there's a tie for fifth-highest number of nominating votes in a categeory, then all the tied nominees are put on the ballot.
For a while, there was at least one tie every year, resulting in at least 21 works on the ballot; but there've been no ties for the past five years. (At least, no ties that resulted in more than five works in a category; I haven't checked whether there were ties that didn't affect the number of works on the ballot, which there could well have been.)
But this year, there were ties in three of the four categories. Two novels tied; three novellas tied; and four novelettes tied. Rather unusual. For details of numbers of nominating ballots, see the abovelinked report.
I have no conclusions or even interesting theories about this; just was surprised and thought it was interesting enough to post about. (I'm guessing there's been plenty of discussion of this in various places, but I haven't seen it.)