Totally depends on style (like yooper said).
15-20% in an American Amber/Red is common
5-10% in an (I)IPA is common
0% in saison, many belgians, lagers is common
Off the top of my head, an Irish Red is fairly dry, non-sweet, but malty. I would err on the side of less for this but then again I haven't research it well enough to give a great recommendation.