I took a quick crack at the correlation implied by table 5 in that paper you linked. Assuming wealth was constant across the ranges specified, I came up with a

I took a quick crack at the correlation implied by table 5 in that paper you linked. Assuming wealth was constant across the ranges specified, I came up with a correlation of 0.45. So meaningful but not high. I personally suspect that it's actually much more highly correlated and that fact would come out if I didn't have to assume wealth was constant for 0-50 and 50-90, but it would be conclusory for me to incorporate that into my numbers.