Larger, expensive cities have not seen large percentage increases in population (ex. San Francisco just 3.7%, Los Angeles 3.1%, NYC about 4.5%)
Cheaper expanding cities experienced significant population growth (Austin 26.1%, Dallas Area 30-50%, Houston 20.3%, Raleigh 43.5%)
The Midwest, particularly South Dakota, North Dakota (except Fargo), Nebraska, and Kansas, Iowa, and Montana experienced little growth
I would expect that in the last four years we've seen these trends continue...people moving, primarily the middle class, out of the more expense cities to more affordable cities.
I bet if you looked at population density per square mile growth then SF, LA and NYC would lead.
I would also guess that the growth in population from high to lo consisted of non home owners in the high areas. There are equity immigrants but I think their numbers are generally overstated.