How did the American work force grow in the years between 1860 and 1900?

Expanded most likely, but what do YOU think..

While we're happy to HELP we won't do all the work for you.
Show us what you have done and where you are having problems..

There's a lot of info about history all over the internet, in books, everywhere. I'm sure your teacher wouldn't give you a subject you haven't been studying, or a subject you couldn't easily research.

Put in the work. We certainly won't spend our Sunday doing it.