I think the universe is 100% dark energy and matter.The question was . . . . . . . . .
"Since we don't know how big the universe is, how is it determined that the Universe is 67% Dark Energy?"
That is of course a very valid question, but it presupposes that we think we know how big the Universe is, which of course we do not know. Without getting into one of those nasty ( ) "infinity" discussions it is of course the meaning of the question - how do we determine the relative size of dark matter in the known Universe.
Does that get us any further? Maybe not?
But it, at least, puts the question on a rational basis.
So, what is the answer?