About 5% of workers aged 55-63 hold multiple jobs.
Between 1994 and 2013, the proportion of workers aged 55-63 who were multiple-job-holders changed from 4.8 to 4.9. During the same time period, multiple job holding rates for workers age 25-54 have declined from 6.4 in Jan 1994 to 4.9 in Dec 2013, according to a 2015 analysis of CPS data.
Lale, E. (2015, April). Multiple jobholding over the past two decades. (fig. 2b) Monthly Labor Review. Retrieved from http://www.bls.gov/