Do you have some sources to back this claim up? As someone who spent 30 years in the UK (give or take) before moving to the US, and having lived on both coasts

Do you have some sources to back this claim up? As someone who spent 30 years in the UK (give or take) before moving to the US, and having lived on both coasts and in the south, something does not sit right about this assertion. Perhaps by unadjusted income it might technically be true, but I suspect not once adjusted for the reality of cost of living.