White Protestant New Yorkers

[H. Ross Peron]

Glazer and Moynihan estimated the "WASP" (i.e. colonial stock + descendants of British immigrants) population at about 5% of NYC in the early 1960s.

That seems quite low for the 1960s when the "silk stocking" district still seemed predominantly WASP. Was he counting Anglo Protestant transplants from other parts of the country who came to New York for work?