Domed Hometown: It could almost be most of them, inasmuch as the average Imperial garden world is a partially-terraformed Mars-type, both they and the non-garden worlds tend to have at least centrally domed towns, and then there’s the aerostat cities and underwater cities to consider, all of which have domes, and so forth.

But, of course, three-fifths of everyone live in space, and habitats don’t fit this design paradigm.  But of the two-fifths who live planetside, it’s almost certainly true.