In fact there is such a source. The US Bureau of Labor Statistics, part of the Department of Labor, publishes all the data you need to come up with real world estimates, and contrary to all those job-loss claims they paint a pretty rosy picture.
In fact, according to the official US government numbers, the number of jobs in "arts, entertainment, and recreation" increased nearly 20% between 1998 and 2008. Even better, total compensation for those jobs (adjusted for inflation) increased almost 30% over the same period.
If you narrow the numbers down to just "independent artists, writers, and performers," the increases were even bigger. In fact those jobs inceased at nearly twice the rate as the industry category overall.
Click the image below to see more details about both categories, or view the figures directly on the Bureau of Labor Statistics website.