I've tallied all featured stories, excluding CYOA movies. Further, I only read the first pages. If there is a tense shift it is not part of my numbers here.
8.9% are written in first person, such as HP7. "I then approach the man?..."
5.4% are written in third person, such as The Adventures of Phoebe McGee: Episode 1, The Lighthouse. "She takes it and steps..."
85.7% are written in second person, such as - just about any story you want to sample.