From Politico:

Matt Seyfang points out that the number to watch in Vermont is 65 percent.

There are 10 “district” delegates allocated by the percentage of the vote in the state’s sole congressional district (aka “Vermont”), and for that group of 10, 65 percent is the break point between a 6-4 split (and a two-delegate margin) and a 7-3 split (and a four-delegate margin.)

I honestly don’t think Obama’s going to win by 30 points, so he may have to settle for a net delegate count of 3 from the state

Politics More On Vermont Math