Koreans' earning power is likely to peak at the age of 54, according to a study estimating how much the head of a family earns, spends, and saves in each period of their life cycle.

According to the study by the Financial Supervisory Service, peak monthly earnings occur at 54, around the time when people's children reach adulthood, with W4.13 million (US$1=W1,116) on average. Of that they spend W2.76 million and save W580,000.

But when they reach the age of 67.8, when they retire and their children are largely independent, their income and expenditure plummet to W1.65 million and W1.21 million, a mere 39 percent and 44 percent of their peak income and spending. Savings shrink to W180,000.

Newly married people save the most money with W730,000, which then gradually dwindles. Their spending increases the most after their first children are born.

Koo Kyung-mo of the FSS said, "The data reflect a characteristic of Korean families where not age but marriage or children affects a household's financial structure."