Civic gets 36 combined, Corolla is 33 combined, Rav4/CRV are both 30 combined. A Prius is 54 combined. Not sure where you are hearing about 70 mpg.
But maybe that's only downhill -- I'm certainly not reaching it :)
But other mini cars like: https://en.m.wikipedia.org/wiki/Volkswagen_Lupo
Or so I hear...