"A growing % of those who come (or stay) are those who are from the region or have a partner with ties to the region."

I think you missed another group that did not exist in 1965 or 1975 or 1985:

A growing % of those who stay are those who are the partners or children of overseas millionaires-with-no-other-ties of any kind with the region or with Ottawa's revenue and taxation offices...