[resu_nimda]

In 1870, nearly half of the workforce worked in agriculture. Almost all of those "jobs" were "lost" over the next century. Did that have a meaningful correlation with unemployment rate?

There is not some fixed amount of "work that needs to be done" that in turn creates a fixed (and steadily diminishing) pool of jobs to draw from. The amount of jobs available is a purely socioeconomic function of who is willing to pay whom for what.

Take Facebook. Do the jobs there carve out some section of the total amount of work that needs to be done today? Not really, a guy made a thing, and convinced people to give him an arbitrary amount of money, and decided to give an arbitrary number of people arbitrary amounts of that money to help him out. A certain number of jobs were created because of the way people decided to distribute their money. Not because they took some of the limited "available job" slots.