What smooth said was correct, but just to clarify: by default, there's a certain amount budgeted per day to be spent from the treasury fund. To spend less, you vote up a proposal that just sends part of that day's budget back to the fund. Informally, we call these "refund" workers.

So the voting level of the refund worker sets the threshold needed to for a proposal to get paid: you need to have more votes than a refund worker proposal that would otherwise eat up all the daily budget.

This means there is no fixed percentage of votes your proposal needs to get funded, it just needs to get more votes than competing proposals (including refund workers).