1. Republicans are 15 percent happier than Democrats.

In a Pew Research Center survey, 45 percent of Republicans described themselves as being very happy, compared with 30 and 29 percent of Democrats and independents, respectively. Republicans have beenconsistently happier than Democrats every single year since Pew began conducting these polls in 1972, and were 10 percent happier than Dems even during Jimmy Carter's term.

2. Older people are 18 percent happier than young people.

In a Harris poll, 44 percent of people aged 65 and over described themselves as happy, compared to 30 percent of 25-to-29-year-olds, 30 percent of 30-to-39-year-olds, and only 26 percent of 18-to-24-year-olds. University of California psychology professor Sonja Lyubomirsky, notes that seniors "are emotionally wiser: They don't spend as much time with people who make them unhappy as young people do, and they don't take as many risks."

3. Residents of Hawaii are 8.5 percent happier than residents of West Virginia.

According to Gallup's annual Well-Being Index, the Aloha State is the nation's happiest, the Mountain State its saddest (and also its most obese.) The other happiest states are Montana, Minnesota, Utah, Iowa, Alaska, Nebraska, and both Dakotas. Scholars analyzing the WBI and taking into account all of its variables—including physical health, working conditions, and access to necessities—produced an additional study concluding that "states with large gay populations, such as Vermont, California, Massachusetts, Washington, and New Mexico, tend to have higher levels of well-being than do states with comparatively smaller gay populations, such as West Virginia, Kentucky, Mississippi, Arkansas, and Ohio."

4. If you're a stay-at-home mom,there's a 36 percent chance that you're very happy.

And if you're a working mom, your chance of being very happy is exactly the same: 36 percent. And both types of moms share a 14 percent chance of being unhappy. But working moms have a 5 percent higher chance of being moderately happy. "What's so interesting is that often women without kids are found to be happier, and yet we are all trained to 'want' a happily-ever-after that includes children,".

5. Those born with two long alleles of the gene known as 5HTT are 17.3 percent happier than those with two short 5HTT alleles.

Maybe it's out of our hands. 5HTT facilitates the transport of serotonin. Alleles are DNA sequences that determine a gene's degree of efficiency. "Genetic factors significantly influence individuals' subjective well- being," write the authors of the study that yielded this stat. "We have identified one particular gene variant—5HTT long—as having a sizeable positive association with self-reported life satisfaction."

6. Married people are 19 percent happier than unmarried people.

43 percent of married people describe themselves as very happy, compared to 24 percent of singles. What's more, married moms are 14 percent happier than single moms. "This is 100 percent financial," asserts Gore of the married mothers statistic. But she also found something surprising: "When I matched moms for income, the single mothers were actually significantly happier."

7. Members of the clergy are 509 percent happier than gas-station attendants.

According to the University of Chicago study that yielded this finding, clergy and firefighters make up the happiest of all professions, followed by travel agents, butlers, and architects. Special-ed teachers are 346 percent happier than amusement-park attendants, pilots are 222 percent happier than construction workers, and actors are 364 percent happier than roofers. And if you're an orthodontist, there's a 99 percent chance that you're happy—according to a study published in the world's only major nonprofit orthodontics-industry journal.