Stephen D. Rogers directed me to a blog entry by John Scalzi at http://www.scalzi.com/whatever/004082.html. In it, Scalzi discusses what he earns as a freelance writer, what he writes in order to achieve that income level, and how skill, luck, and circumstance all play a role in his success.
Scalzi averages $100,000 a year from freelancing.
No matter what part of the country you live in, that's nothing to sneeze at. Even so, one thing writers never seem to take into account when discussing annual incomes and billing rates is their local costs of living. Gross income isn't always the most important number when determining financial success as a freelancer. More important is buying power. What does your income get you?
For example, my monthly payment--principal, interest, taxes, and insurance--on my current home in Waco, Texas (a modest three-bedroom brick home) is less than what I paid to rent a one-bedroom apartment in a Chicago suburb in the early 1990s. What I pay for automobile insurance for three vehicles and three drivers isn't much more today than I paid for one vehicle and one driver when I lived in Chicagoland. And so on.
Although I'm not earning an income comparable to Scalzi, the low cost-of-living locally means my buying power is pretty darned good.
I'd suggest that all writers considering a leap to full-time freelancing take a stronger look at their local cost-of-living and potential buying power than at some arbitrary income level. You may need much less--or much more--to maintain your lifestyle than you think.