Line graph with dates on horizontal axis

i know this is probably an easy fix, but i can't get excel to display the actual dates across the horizontal axis. I figured out how to do it by month, year, etc...but i need the actual date displayed. Any help? Example - dates are 12-31-11, 3-31-12, 6-30-12 it adds them as 12-1-11, 3-1-12, 6-1-12.

That worked. Thanks so much for the help. It was driving me crazy.