Holding down one job can be hard enough sometimes, let alone two or more. But that’s the reality faced by many Americans, which includes an astounding number of teachers.

About 13 million people in the U.S. work more than one job, according to the Census Bureau. That represents roughly 5% of the American workforce. And that percentage is significantly higher for teachers, according to a survey by social app Fishbowl. The survey asked 660 teachers: Outside of being a teacher, do you supplement your income with part-time work on weekends or school breaks?

Just over 49% of teachers have answered with yes.

The Census report also states that women are more likely to have multiple jobs, and teaching happens to be one of the most female-dominated professions. According to the National Center for Education Statistics, about 77% of public school teachers were female while 23% were male in during the 2015–16 school year.

Not just seasonal

Many people pick up extra work around the holidays. But according to the data, most people with multiple jobs held those positions year-round. That amounts to between 7.6 million and 8.2 million people according to Census data. The same could be said for many teachers.

New York City School Teacher Kelly Finlaw tells Yahoo Finance that at times she's had "no social life" due to working extra hours. Most teachers that she knows work in ‘per-session'. That means they have a second job at the school, or somewhere within the NYC DOE that is paid hourly. Finlaw has worked per session in the past. She has also held other side gigs and is always looking for ways to make extra money.

"We have an after-school fitness club that I ran with my friend for about 5 years,” she said. “Then the budget ran out for the program. I coached the basketball team for 10 years, took a two-year break, and started back again last year. I go in to my school in the summer and paint murals for extra money. I wrote and illustrated a book that's on Amazon and am working on another. I have an Etsy shop. I pick up any commission gigs that I can get."

Finlaw's sister lives in Indiana where teacher pay is significantly lower than it is in New York. Some of the teachers at her kids' school have second jobs bagging groceries and working at retail outlets at stores like TJ Maxx.

"I will start working another job on Saturday. I'm not making it just teaching. I love teaching, but I am always poor." said an elementary school teacher in Michigan.

"I have a seasonal job for the summers and Christmas break at Chick-Fil-A. I usually use the money I make there to get ahead on bills and or buy that one awesome thing for my classroom," said another teacher from Georgia.