The differences in starting salaries for STEM majors versus those who study the humanities have been widely publicized. Now, a new study looks at how those differences add up over a lifetime of earnings – and the results are staggering. 

The lowest paid graduates, early childhood education majors, earn just $39,000 annually mid-career, while the highest paid petroleum engineering majors, make an average of $136,000 per year. Over a career, that difference amounts to more than $3 million, according to the report The Economic Value of College Majors by economists at Georgetown University. 

Among the major fields of study, architecture and engineering students earn highest average salary--$83,000 per year, and education majors earn the lowest--$45,000 per year. 

Related: 10 Public Universities with the Worst Graduation Rates 

The study finds that generally it’s still worth it to go to college. The average bachelor’s degree holder makes $1 million more over a lifetime than a person with just a high school diploma. 

A separate report released last fall by the Federal Reserve Bank of New York found that the value of a bachelor’s degree has reached an all-time high of around $300,000. Researchers found that it takes about 10 years to recoup the cost of a degree, a historically low level, down from close to 25 years in the late 1970s and 1980s. 

So those education majors should still go to college, but they might be smart to look for more moderately priced options and to be more wary about taking on debt than their engineering peers.