Unpaid interns suffer all sorts of indignities: you don't know when someone will hire you for real, you don't get paid, you might be doing the dullest work ever, and depending on where you work, you might not even be protected from workplace sexual harassment.
Also, the Labor Department isn't counting you.
The department that tracks all sorts of minutiae about Americans: who works where, for how much money, where they spend it, and even what they do all day, doesn't have an official, running count of interns of any sort. And while paid interns at least get counted in things like monthly payroll reports, unpaid interns are not included in any of that data.
Interest in unpaid internships has ramped up dramatically in the past few years, as lawsuits against firms that have used unpaid interns, like Fox Searchlight and Condé Nast, brought them into the spotlight. If the number of Google searches is any indicator, people are increasingly searching for unpaid internships, whether because they want work opportunities, news stories, or a dose of outrage.
And for all that sound and fury, we don't really know much about this area of the labor economy: who's doing this work, what industries they're in, and how that population has changed, particularly in the wake of the recession. And it's not just the Labor Department: the Census Bureau and Education Department don't keep running counts on interns, either.
Some people have tried to count. Intern Bridge, a college recruiting consulting firm, estimates there are between 1 and 1.3 million people enrolled in "experiential education" programs like internships and cooperative education programs.
It's not just that it would be an interesting statistic. Knowing how many interns there are would provide a more complete picture of work in the United States (though unpaid interns in the private sector have legal limits as to how much their presence can benefit the employer, among other things).
Counting interns would also show which industries are bringing on these trainees most...not to mention which industries have a massive glut of wannabe full-time employees banging down their doors.