If your #1 goal is to practice in California, then you just have to keep taking & retaking the exam until you pass it. The percent of non-California educated dentists who pass won't mean anything if you have your sights set on nowhere but California after graduation.
Clinical board exams are nothing to be afraid of. You take them, try your best, and hope you pass. You can have the best handskills and do the best clinical work, but fail because you didn't fill out your paperwork properly. Therefore, you can't get discouraged if you fail b/c they are very subjective exams.
Sorry I'm not much help regarding the stats. I don't know where you can find stats, but there are prep courses out there to familiarize non-Cali educated students with the nuances of the exam. Some of my classmates took these courses and I saw them practicing for the exam prior to graduation b/c they have the full intent of practicing in California and nowhere else.
