The Gallup-Healthways Well-Being Index found U.S. adults who were married had the highest levels of well being -- 68.8 percent -- followed by singles, who had a well being index score of 65. Widowed people had a score of 63.5, domestic partners had a score of 63.3, divorced people had a score of 59.7 and separated people had a score of 55.9.
The Gallup-Healthways Well-Being Index data involved a range of subgroups including 6,000 separated U.S. adults to more than 190,000 married adults.
"The differences in well being by marital status were some of the largest Gallup finds within any demographic subgroups," Gallup officials said in a statement. "For example, the roughly 13-point difference in well-being index scores between the highest and lowest scoring marital status groups compares with a maximum 5.2-point difference by racial group, a maximum 3.2-point difference by age group, and a 0.1-point difference between genders."
The well-being index score is an average of six sub-indexes, which individually examine life evaluation, including emotional health, work environment, physical health, healthy behaviors and access to basic necessities. The index is calculated on a scale of 0-100 -- a score of 100 would represent ideal well being.
The survey was conducted from Jan. 1-Dec. 31, 2011, with a random sample of 353,492 adults. The margin of error for all adults was 1 percentage points, but for the subgroup separated adults it was 2 points.