A polling agency has said that the year 2011 was a little different from 2010 in terms of the levels of stress and happiness the Americans experienced.
The Gallup polling agency averaged the results from its Gallup-Healthways Well-Being Index, a day-by-day measurement of America's mental state that includes some 350,000 surveys conducted throughout the year.
The yearly average showed that 49.1 percent of respondents experienced a lot of happiness and enjoyment without a lot of stress and worry in 2011, compared with 48.4 percent of Americans who said the same in 2010.
In both years, about 11 percent of Americans experienced a lot of stress and worry without a lot of happiness and enjoyment, LiveScience reported.
While the yearly stress averages between the two years was essentially the same, 2011 only had one day where more than 15 percent of people felt a lot of stress, whereas 2010 had six days.
Gallup previously determined that high stress/low happiness days tend to occur on or close to widely reported negative news events - 2011 was no different.
The most stressful day in 2011 was 27th April, around the time when an outbreak of tornadoes killed some 300 people and caused nearly 11 billion dollars worth of damages.
Tied for second place was tax day 18th April and days near several international crises, including the anti-government protests in Egypt and the leaking of radioactive materials into the ocean from the Fukushima Daiichi nuclear power plant in Japan.
On the flip side, the happiest day in 2011 was Christmas, followed closely by Thanksgiving, Easter Sunday and Independence Day.