Despite the happiness payoff, Americans are delaying marriage.

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Diehard romantics say you can't put a price on love, but a pair of European economists disagrees. In 2002, the two men calculated the monetary worth of marriage at $100,000 per year [source: Financial Times].

Despite the potential payoff, people in the United States are putting off marriage later in life than ever before. In correlation with the rising life expectancy, men and women are giving themselves more time before exchanging vows. The average age for an American woman to get hitched rose from 20.8 to 25.3 from 1970 to 2003 [source: U.S. Census Bureau]. Additionally, more adults are living the single life, thanks in large part to the higher divorce rate. According to U.S. Census data, 90 percent more single-person households existed in 2005 than in 1970 [source: Beckwith].

Over the past 30 years, marriage has become more of a social choice than a necessity, but all it takes is a few episodes of "Sex and the City" to see that Western culture still favors cohabitation. Humans' animal instincts are wired for mating in one way or another. Moreover, a pervasive idea exists that discovering a soul mate brings joy and makes life worth living. Perhaps we aren't far off the mark; studies have shown that married people tend to earn more money and live longer than singles. Marriage also appears to promote better health. The Centers for Disease Control and Prevention (CDC) found that husbands and wives are less likely to smoke or drink heavily, experience frequent headaches and suffer from psychological problems than people who aren't married [source: Stein, Song and Coady].

But betting on marriage to bring you happiness may be a risky gamble. After all, the odds of holding on to that perfect partner forever have been whittled down to a coin flip -- about 48 percent of marriages end in divorce [source: Centers for Disease Control and Prevention]. Nevertheless, psychologists have pointed to marriage as the single most reliable happiness indicator. Across nations and ethnic groups, people report greater happiness from marriage than career, community or money [source: Seligman]. A 2005 survey from the Pew Research Center substantiates these assertions. Forty-three percent of married respondents reported that they were "very happy," compared to 24 percent of unmarried individuals [source: Pew Research Center]. Those results were consistent for all age groups and genders.

As any good scientist knows, correlation does not always equal causation. To close the case on whether marital bliss trumps the single life, we must deduce which comes first: happiness or marriage?