The average person born in the later years of the baby boom held 10.8 jobs from age 18 to age 42. Nearly two-thirds of these jobs were held from ages 18 to 27.
Individuals born from 1957 to 1964 held an average of 10.8 jobs from ages 18 to 42. These baby boomers held an average of 4.4 jobs while ages 18 to 22. The average fell to 3.3 jobs while ages 23 to 27 and to 1.9 jobs from ages 38 to 42.
Jobs that span more than one age group were counted once in each age group, so the overall average number of jobs held from age 18 to age 42 is less than the sum of the number of jobs across the individual age groups.
These findings are from the National Longitudinal Survey of Youth 1979. For more information see "Number of Jobs Held, Labor Market Activity, and Earnings Growth Among the Youngest Baby Boomers: Results From a Longitudinal Survey," (PDF) (HTML) news release USDL 08-0860. Note that a job is defined here as an uninterrupted period of work with a particular employer.
Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily, Youngest boomers: 10.8 jobs from ages 18-42 at https://www.bls.gov/opub/ted/2008/jun/wk5/art01.htm (visited September 25, 2023).