I am highly suspicious of this report: Estimate puts N.O. population at 70 percent of pre-Katrina.
If you read through the article, you see the claim is based on postal deliveries to addresses. Hmmmm. If an address had a family of, say, four or five before Katrina, but now the house is occupied by one or two, that can skew the actual result by a large factor. With entire swaths of New Orleans East, the Lower 9, and Lakeview unoccupied, I can not see how 7 out of 10 have returned.
(My parents often had mail delivered to their flooded house in Lakeview before it was torn down. I wonder if that is one of the addresses counted....)