A new study from Keirsey Research, which conducts public surveys, found that the happiest Americans earn more than $75,000 in annual wages, are extroverted, healthy and engaged, according to CNN. The researchers examined 3,900 adults from ages 18 to 70 who completed the personality test.

Test subjects were asked how happy they were in their lives overall, and were asked questions about their gender, employment, marital status and other aspects of their lives. Approximately 74 percent of respondents who were considered extroverted were happy, compared to 56 percent of introverts.

"Extroverts recharge themselves through contact with other people and introverts recharge themselves through solitary time," Kip Parent, chief executive officer (CEO) of Keirsey, told the news provider. "Maybe it's that when we're drawing our energy externally through other people, that gives us a little bit more positive charge."