User blog comment:PunjiChocoBerry/Random Boost Chance!/@comment-25889587-20150428164436


 * Energy Drains 25% Slower: 4 (8%)
 * 30% less energy drain when colliding: 2 (4%)
 * Revives once with 80 energy: 4 (8%)
 * Base speed 30% faster: 5 (10%)
 * Invincible to 70% of obstacles: 6 (12%)
 * Gold Coin Boost: 3 (6%)
 * 15% Point Bonus: 3 (6%)
 * Fast Start: 7 (14%)
 * Magnetic Aura: 6 (12%)
 * Rescue from holes twice: 4 (8%)
 * Potions restore 25% more: 5 (10%)
 * Double Coins: 3 (6%)

Opened up 52 times. Percentage approx. 50. Just remember that every time you opened another random boost, you can't have the same one again.

I seriously think they are uniformly distributed, as in every boost had their chances :P