Can "some" be more than 50%?

Solution 1:

In all of the dictionaries that I checked, "some" is used for unspecified amounts and quantities, and also for "a considerable number or quantity." (AHD) In none of the examples did it make sense to ask "what percentage are they talking about?"

Because it's used for unspecified things I don't think it makes sense to talk about number or percentage, even in situations where there is a finite amount of something. For example someone gestures to a bowl of candy and says "Have some." Does "some" mean more than half of the candy, or a few pieces? It doesn't indicate because it's for an "unspecified amount." Someone faced with a bowl of candy will probably take two or three pieces, regardless of whether the bowl contains 100 or 10 pieces.

"Some of the people in the professor's class didn't understand the lecture." Does "some" mean more than 50%? No, it means an unspecified number.

You asked who uses "some" to mean more than 50%. I don't think anyone does because the word means a vague amount with no number attached. If they were referring to a group of 4 people and said "some people." it could mean anything; one, two or three people.

Solution 2:

Mathematical probabilities and history aside, "some" has an uncertain feeling which would lead to the assumption that it meant: 'less than the majority.' To refer to more than 50%, it would be more common to use "most of...". (US)

Solution 3:

If the sentence with "most" instead of "some" is true and that matters, you shouldn't use "some". This is due to Grice's maxim of quantity:

Make your contribution as informative as is required (for the current purposes of the exchange). Do not make your contribution more informative than is required.

from Cooperative Principle.

However, what matters is whether "some" would be misleading. It will be okay even if more than 50% holds, provided you clarify. For instance, you could say "some, in fact most".