WASHINGTON — A World Bank report shows a broad reduction in extreme poverty — and indicates that the global recession, contrary to economists’ expectations, did not increase poverty in the developing world.

The report shows that for the first time the proportion of people living in extreme poverty — on less than $1.25 a day — fell in every developing region from 2005 to 2008. And the biggest recession since the Great Depression seems not to have thrown that trend off course, preliminary data from 2010 indicate.

The progress is so drastic that the world has met the United Nations’ Millennium Development Goals to cut extreme poverty in half five years before its 2015 deadline.

“This is very good news,” said Jeffrey Sachs, director of the Earth Institute at Columbia University and the United Nations’ special adviser on the Millennium Development Goals. “There has been broad-based progress in fighting poverty, and accelerating progress. There’s a lot to be happy about.”