This requires a little math, but it will always depend on the number of characters you have already unlocked on Zooba.
If you divide them by 5 and consider only the decimals, you will get the exact percentage of rerun probabilities for each character!
For example: If you have 16 Characters: 16 divided by 5 equals 3. 2. This means that your probability will be 20%!
If you have 7, then your probability will be 40% because 7 divided by 5 is 1, 4.
You can learn more about earning items by tapping here.