Who are the happiest Americans? According to a new study, they may be extroverted, earning more than $75,000 a year, healthy, and engaged.

The analysis was conducted by Keirsey Research, an organization that looks at how personality relates to a person's preferences in consumer choices, political opinion, and a variety of other factors.

The survey looked at 3,900 adults ages 18 to 70 who had completed the Keirsey Temperament Sorter II, a personality test. Participants answered questions about how happy they were with life overall, then provided a variety of information about their gender, employment, marital status, and other elements of their lives. Because they had also completed a personality test, survey analysts were able to also look at that in relation to happiness.

They found that the three highest factors affecting happiness are personality type, household income, and health. About 74 percent of extroverts are happy, vs. 56 percent of introverts. That's a larger gap than Kip Parent, CEO of Keirsey.com, expected, but it makes sense in terms of how people with different personalities operate, he said.

"Extroverts recharge themselves through contact with other people and introverts recharge themselves through solitary time," Parent said. "Maybe it’s that when we're drawing our energy externally through other people, that gives us a little bit more positive charge."

For household income, 73 percent of those earning above $75,000 per year were happy, vs. only 59 percent for those under $50,000. It's perhaps not surprising that money brings happiness to some extent, but the survey found that $75,000 is the "magic point": Beyond that, greater incomes do not seem to bring greater happiness, Parent said. Similarly, below $50,000, people were consistently less happy.

And for health, 72 percent of people who say they're in "excellent" or "very good health" are happy, vs. only 39 percent who say their health is "only fair" or "poor."

"Lots of money doesn’t buy happiness, but certainly having enough money helps a lot," he said.

In general, more happiness comes with age, as several studies have reported in the past. But there is an age bracket where happiness dips noticeably: among 35- to 44-year-olds. Parent suggests that is because issues with children are the heaviest, and related it to another finding of the survey: that people with children who are separated or divorced tended to report unhappiness.

When it comes to relationships, people who are engaged are the happiest, whereas those who are separated but not divorced are the least happy, the survey found. But after coming out of the limbo of separation, people seem to be happier, Parent said. Married people are somewhat happier than divorced people, but even they have about average happiness, he said.

And here's the political piece: Democrats and Republicans have about the same level of happiness; members of the Green Party said they were the least happy, followed by Libertarians.

"The unhappy people seem to be the people with stronger views," he said.