How to tell when i m ovulating from BBT Chart

Hi, i am confuse on which day i m actually ovulate from my BBTchart, hope someone can give me an advise..thanks !! me and husband has been TTC for 2 years, and his is my 1st time on HSG test.

CD1 - 36.38
CD2 - 36.17
CD3 - 36.27
CD4 - 36.20
CD5 - 36.25
CD6 - 36.28
CD7 - 36.35
CD8 - 36.04
CD9 - 36.08 (Intercourse)
CD10 - 36.24 (HSG test)
CD11 - 36.23
CD12 - 36.28 (intercourse)
CD13 - 36.46
CD14 - 36.50
CD15 - 36.53 (intercourse)
CD16 - 36.53
CD17 - 36.50
CD18 - 36.61