Those numbers seem closer to entry-level pay positions to me rather than median numbers. I was offered a position as an entry-level analyst (before I finished my applications for the doctorate) at $45k at the New Mexico Health Department. The range went up to $58k for that position. Epidemiologist positions in both the MA and CO health departments started in the high $48-50k region and stopped in the mid-$80k region.
Then again, maybe this chart is over the course of the history of time?
OP: The range varies considerably by discipline and work environment. You could earn anything as low as $30k/yr to something as high-paying as $500k/yr if you become a cushy executive of some company (could be underestimating). So it really runs the gamut.