Multiple job holding seems high at nearly 8.4 million, here.
But as a percent of the employed it is not, currently at 5.2%. In the go-go 1990s it was above 6%.
Multiple job holding generally is a sign of opportunity and good times, not economic stress and bad times. Obviously there is always a percentage of the workforce which can't find full-time work and works two part-time jobs. They now number almost 2 million, a very small part of the employment universe, which is near all-time highs in the range of 161 million.