The U.S. economy grew more slowly over the past three years than the government had previously estimated, held back by more frugal consumers and steeper spending cuts by state and local governments.

The Commerce Department says the economy expanded at just a 2 percent annual rate from 2012 through 2014, down from a previous estimate of 2.3 percent. Nearly all the weaker-than-expected growth occurred in 2013, when the government now says the economy expanded just 1.5 percent, much less than its previous 2.2 percent estimate.

The revisions show that the economy's already-modest growth since 2011 was even weaker than thought. The recovery since the Great Recession officially ended in June 2009 has been the slowest of any since World War II.