What Are the Most Stressful Jobs in America?

I'm trying to think right now of the most stressful job in America. I couldn't think of anything more stressful than being the president. Besides being criticized or praised day in and day out, what could possibly be more stressful than making decisions for an entire country?

But, that job doesn't make the list. So which ones do?

Most Stressful

1. Enlisted military personnel
2. Military general
3. Firefighter
4. Commercial airline pilot
5. PR executive
6. Senior corporate executive
7. Photojournalist
8. Newspaper reporter
9. Taxi driver
10. Police officer

Least Stressful

1. University professor
2. Seamstress/tailor
3. Medical records technician
4. Jeweler
5. Medical laboratory technician
6. Audiologist
7. Dietician
8. Hairstylist
9. Librarian
10. Drill press operator

I would have to agree with most of these. But...how is a professor less stressful than a librarian?