The Bureau of Labour Statistics has released a report on rates of people holding multiple jobs in 2012. Nationwide, 4.9 per cent of all employed people hold more than one job, and this rate has not changed over the last few years. However, multiple-job holding rates vary across the states dramatically, ranging from 3.4 of workers in Florida holding multiple jobs to 9.5% in South Dakota:
Multiple-job holding is much more common in the North than in the South, especially in the Great Plains states (7.3% multiple-job holder rate) and New England (6.0% rate).
A 2010 BLS report discusses some of the demographics of multiple-job holders, and the reasons people take more than one job. Moonlighting rates have been very stable over time, and do not seem to be strongly tied to the overall job market or unemployment rate.
Women are more likely to hold multiple jobs than men, and whites are more likely to hold multiple jobs than people in other racial groups. Multiple-job holding also tends to be more common among people with higher educational attainment, with holders of advanced degrees nearly three times as likely to work two or more jobs than people without a high school diploma.
The main reasons people take on multiple jobs are economic — to meet expenses or make extra money. A decent share of multiple-job holders, though, are in their second jobs for non-economic reasons — to get experience in a different business, or because they just enjoy the work. Unsurprisingly, these reasons also are correlated with education — the higher a person’s educational attainment, the more likely they are to work a second job for non-economic reasons.