This is sticky information because dealer do not want to express information to the public but they would love it if you apply for an auto loan in your local car dealer.
There are multiple websites that can help you get approved for a car loan but A dealer will never let you know how many car buyers get approved.
There are to many factors to set into place for that kind of answer. Demographics is a huge concern and income. So when it comes to denials for car loans you'll never get a straight answer but most dealers will work to get you approved at the best rate.