IStock Photo 1461915 © Bebebailey

If you're interested in earning a six-figure income, pack your books, head off to school—and plan on staying there for a while. Because if you don’t put in the class time, you may find it impossible to ever make a salary that breaks six figures.

Overall, the odds a person 15 or older has an income of $100,000 or more are 1 in 18.05. Those may seem like reasonable odds, but when you factor education into the equation, things get very lopsided. If you've reached the age of 25 or older with no more than an elementary school education to your name, the odds you have an income of $100,000 or more are a dismal 1 in 235.2.

High school improves things somewhat. With some high school education, the odds someone 25 or older has an income of $100,000 or more are 1 in 130.6; obtaining a high school diploma betters that to 1 in 52.92.

It's only when college kicks in that the odds improve dramatically. The odds a person 25 or older with an associate's degree has an income of $100,000 or more are 1 in 25.1; a bachelor's degree improves that to 1 in 8.37.

Advanced degrees make the odds of earning $100,000 or more a year even better. The odds a person (25 or older) with a master's degree has an income of $100,000 or more are 1 in 5.43; with a doctoral degree, 1 in 2.67 (37%).

Of course with lots of schooling often comes loads of debt. According to the College Board, the median amount owed by those who earned bachelor's degrees at four-year public colleges in 2007-08 was $17,700, and for those at four-year private colleges, $22,375. Even a six-figure salary can seem less impressive when the first of the month rolls around and another big check has to be written to pay back those student loans.

That debt can put extra pressure on graduates to find steady, well-paying jobs. Unfortunately, a sour economy has made that quest more difficult. Recent college graduates are having a hard time finding any work, let alone high-paying jobs.

Maybe you've decided that that MBA is not worth the price tag. If so, there's an alternative path to highly paid employment. Enjoy the movie Remains of the Day? Hankering to be a gentleman's gentleman (or a lady to that gentleman)? Look into being a butler, or "household manager," to those who already have the big bucks.