The U.S. economy went into recession a year ago, with sharp declines in payrolls, incomes, sales and production, among other indicators, according to the National Bureau of Economic Research.

In a statement released this week, a panel of economists on the nonpartisan group's Business Cycle Dating Committee said the nation's economic activity peaked in December 2007 and has been declining ever since.

"The peak marks the end of the expansion that began in November 2001 and the beginning of a recession," the group said.

In the statement, the group defines a recession as a "significant decline in economy activity spread across the economy, lasting more than a few months, normally visible in production, employment, real income, and other indicators."

It said a recession begins when the economy reaches a peak in activity and ends when it hits bottom.

Among other indicators, the group points to payroll and income  declines earlier this year, followed by a downturn in industrial output, manufacturing and retail sales.     

These indicators and others "met the standard for a recession," the group said.