Your parents might have worried when you chose Philosophy or International Relations as a major. But a year-long survey of 1.2 million people with only a bachelor's degree by PayScale Inc. shows that graduates in these subjects earned 103.5% and 97.8% more, respectively, about 10 years post-commencement. Majors that didn't show as much salary growth include Nursing and Information Technology.

Wow. Things have certainly changed a great deal in the past 10 years. Here is the definition of "mid-career:"

Full-time employees with 10 or more years of experience in their career or field who are Bachelors graduates.

For the graduates in this data set, the typical (median) mid-career employee is 42 years old and has 15.5 years of experience.

I get the impression that in general, there is a stronger correlation between age and salary than there is between merit and salary.

Salary Increase By Major | WSJ