It appears the economy can really stress a country out.

A new Gallup poll finds that the most stressful day of 2010 for Americans was Dec. 1, the day after Federal Reserve Chairman Ben Bernanke said he was concerned the economy wasn’t growing fast enough to reduce the unemployment rate.

That was also the day after Congress allowed federal unemployment benefit extensions to expire.

The benefits were later reinstated under a compromise between the Obama administration and congressional Republicans.

About 18 percent of Americans said they were stressed out Dec. 1, compared with 11 percent on the average day. Gallup said it’s the third year in a row that the most stressful day of the year coincided with bad economic news.

The polling company cautions that it’s impossible to definitively determine the causes of a high-stress day, but they often occur on or close to high-profile negative news stories. The country’s relative stress and happiness was measured using its Gallup-Healthways Well Being Index, which is based on interviews of about 1,000 U.S. adults each day.

In 2009, the most stressful day was Jan. 29, the day after the House passed a huge economic stimulus bill, shortly after President Barack Obama took office.

For 2010, Gallup said other stressful days included Sept. 27, when the Midwest was hit with severe flooding, and Oct. 12, the final day of preparation to rescue trapped Chilean miners.

On the whole, however, the Gallup poll found that Americans were slightly happier in 2010 than in 2009.

The happiest day of 2010? That would be Christmas, when 65 percent of Americans said they were happy. Other happy days included Mother’s Day and the Sunday before Labor Day.