What are the odds of getting a holo in individual MtG packs? Cuz i bought a judgement booster and pulled a holographic Spurnmage Advocate, and i had a holo Mirari but I traded that a while ago

it seems to me that in the last ten packs i've gotten i have maybe pulled two foils. i'm not sure what the exact odds are, it prob says on the packs.

Oh yeah, I just saw that...it says on the pack, premium cards come in 1:70 cards...that's almost 5 packs. thanks