How rare are triple 800's on the SAT Math Level 2, Physics, and Chemistry Subject Tests?

@CalBearsMom (post #10)
I don’t know the statistics which would show the degree of correlation between the AP grades and the SAT Subject Tests scores (I would assume it’s high), but in my observations 5s on APs don’t automatically translate into SAT’s 800s. I’ve seen kids in advanced calculus classes score in low 700s on the SAT Math Subject Tests; same with Physics, Chemistry, Bio, and History.