The World Bank is reducing its forecast for the global economy this year — again.

The aid agency now predicts that growth will reach 2.4 percent this year, down from the 2.9 percent it had foreseen in January and unchanged from a tepid 2015.

A big problem is that commodity-exporting countries are struggling with low prices for raw materials.

The U.S. economy is forecast to grow 1.9 percent, down from 2.4 percent in 2015. The eurozone is expected to grow 1.6 percent, the same as last year.

The World Bank slashed its forecast for Japan's growth to 0.5 percent from the 1.3 percent it expected in January. Its forecast for China remained 6.7 percent.

In recent years, the World Bank and International Monetary Fund have consistently downgraded their initial forecasts.