3 million college graduates — aged 25 to 64 — were surveyed by the U.S. Census Bureau about their undergraduate studies. The project found amazing results: did you know geology majors and petroleum engineers were making $120,000? While their co-graduate counselors earned just $29,000 (so much for all those Psych majors). Today, it's not just about having a degree; majors do matter — and here's why.