Unemployment as a Concept

I took a US Economic History class while back. One of the things I hadn't realized was that the concept of someone being "unemployed" is realtively new. Prior to industrialization and the subsequent specialization of labor, workers weren't really considered unemployed. Then again, in 1800 about 80% of the US labor force was engaged in agriculture, and I have yet to find a farmer that didn't have something to do.

Google's new Books Ngram Viewer provides an interesting look at when "unemployment" came about.

Prior to 1900 we had employment, but not unemployment.