STEM jobs are the jobs related to the fields of science, technology, engineering, and mathematics. Each of these fields are further divided into the different branches, which covers a lot of careers. The market demand for the graduates in any of the STEM field is very high as compared to the other graduate with the art major. The reason for that is the skill level, because a MD, engineer or software developer, has more useful skills regarding the availability of the jobs in the market. A doctor in I.C.U or a chemical engineer working in an oil refinery or a pharmaceutical factory is no doubt more useful to the society than a musician or a folklorist, that is why they get highly paid as compared to the other jobs. But that does not mean that, lets say an artist is less skill full, but they are cases where musicians who have worked hard, now own their own record label companies and are very successful in earning millions like rapper DR. Dre who owns a mansion in L.A. which is simply a dream for an ordinary Doctor. But it is a rare example as we see very few examples like Dr. Dre while the STEM jobs consume almost every related graduate fresh out of the college.
The Industrial Engineer gets paid $38.63 per hour, or a physicist gets paid $77 per hour(according to http://www.iseek.org/careers/stemcareers ) which is 26 percent more than average salary of their non stem counter parts.(http://www.esa.doc.gov/sites/default/files/reports/documents/stemfinalyjuly14_1.pdf).