The Wall Street Journal ran--I don't think a subscription is required, but it might--the results of "a year-long survey of 1.2 million people with only a bachelor's degree by PayScale Inc". (More on the survey's methology here.)
One table shows the "Starting Median Salary" for "50 popular Bachelor's degree majors". Economics is ranked 13th with a reported $50,100. Seven types of engineering, computer science, and physics are ranked higher. (Two of the remaining majors ranked above economics are "Physician Assistant" and "Construction", both of which I would be very surprised to learn constitute a "major" at many schools.) The unweighted median of the 50 majors is $40,850.
Another column of the same table shows "Mid-Career Median Salary". Here, economics ranks 5th, behind only chemical, computer, electrical, and aerospace engineering. (The number reported is $98,600; the unweighted median of the 50 majors is $72,000.)
Just to be clear: I make absolutely no claim that economics training accounts for all, or even a a substantial part, of the apparently high salaries of economics majors. A substantial part is undoubtedly due to the kinds of students who choose to major in economics. And, as a couple of commenters reminded me the last time I posted about salaries, the availability of majors differs importantly across schools. (For instance, Duke doesn't have an undergraduate business management major; a lot of kids interested in finance or general management there major in economics. A lot of less selective state schools, on the other hand, do have business management majors.)
Still, it's at least a little interesting. Especially when you consider that this survey omits folks with MBAs, JDs, MDs, and other graduate degrees.