How hard is it to get a party sticker from an infinite infinity chest PvZ GW2

@LegibleAbyss7 Very good question actually. I have played Infinity Time loads of times with my brother. I find that whenever we get the Infinite Infinity Chest, we get party character stickers about half or 1/3 of the time each. They do not seem that rare, but it can take a while to get the party character pieces sometimes.