I think we have to assume fav%/unfav% directly translate into vote for / not vote for; Can you do that?
To attest to accuracy--notice the wording "final"--means close to election. I haven't checked, but I bet the "final" by most polling agency are not that far off. CNN might quote Gallup. Assuming Gallup is objective, CNN might say "according to Gallup" etc etc. Where does the bias come from?