NEW YORK — Bill and Melinda Gates are optimistic about the future for the world's poor and say three myths are hampering progressive efforts to fight disease and poverty.

In sixth annual letter published by their foundation Tuesday, Bill Gates writes that the first myth floated by some is that poor countries are doomed to stay poor. He says that's not true and predicts that by 2035 there will be almost no poor countries left in the world.

In an interview in New York City, Gates says the second myth is that foreign aid is wasteful.

Melinda Gates writes the case against the third myth, that saving lives leads to overpopulation.

The Seattle, Wash.-based Bill & Melinda Gates Foundation is the world's largest charitable foundation, paying out $28.3 billion in grants since its inception 13 years ago.