The study released recently by the U.S. Bureau of Labor Statistics tracked the employment histories of the "younger boomer" age group from 1979 to 2005. Its primary finding was that individuals born from 1957 to 1964 held an average of 10½ jobs while they were 18-40 years old.

It found that job tenure tended to increase with age but that percentage growth in inflation-adjusted hourly earnings generally did not.

The study relied on annual or biennial interviews with 9,964 U.S. workers who were 14-22 when first interviewed and 39-48 when interviewed most recently.

As might be expected, the survey found that job changes were most frequent in workers’ younger years.

The participants reported an average of 3.8 jobs while they were 18-21 and an average of three jobs while they were 22-25.

At the other end of the age period, workers reported an average of two jobs from 36 to 40. The survey found that this boomer age group also tended to have large numbers of short-duration jobs.

The findings underscore current warnings by financial planners that workers must assume greater responsibility to save for their retirements.

With such short job tenures, workers are less likely to be covered by or become vested in employer-sponsored pension plans.

The report said inflation-adjusted hourly earnings grew by an average of 6.3 percent a year from ages 18 to 21 and by 6.5 percent a year from ages 22 to 25.

Average earnings growth then slowed to 4 percent a year from ages 26 to 30, then to 3.6 percent annually from ages 31 to 35 and 2.5 percent a year from ages 36 to 40.