Sensitivity slider: Certain numbers can't be used

In the sensitivity slider in the options menu, a lot of numbers get skipped and cannot be on, such as 3, 6, 10, 13, 17, etc.

What I expected to happen was...:
Be able to slide onto those certain numbers.

What actually happened was...:
It skips over the numbers.

Steps to Reproduce:
1. Try to move the slider slowly from yawn to HYPERSPEED!!!!!