Temping Newbie! Help! What day did I ovulate??

What day did I ovulate based on my chart?? Temp dropped significantly on day CD15, then on CD 16 temp spiked .62 degrees ( however was just under coverline) in CD 17 temp went up a little more and at that point was above coverline and has stayed there. I am trying to figure out if I O’d on CD15 or 16. Can anyone take a look??? TIA! :)