Actually, the gearing is closer to 94 gear inches on a 20" wheel like the OP is asking about.

To answer the question, an 11 is the smallest cassette cog I have heard of. If you want a higher gear, you probably need to look for a larger chain ring, which could impact ground clearance.

EDIT: For a flat bar bike, I would think 94 gear inches is probably high enough unless you are bombing down hills... then I would coast.