I am trying to come up with a formula that will result in a score of 1 to 100 (never anything lower or higher). I have two numbers that I can use to come up with this score, a specific percent and an average percent (from all of the others in the set).

The score would essentially not be able to reach the upper or lower bounds, just get infinitely closer. The idea would be to assign a score of 50 if the specific percent matched the average percent, and scale from there. I know I've done something like this in the past, but I've been racking my brain off and on all day and haven't been able to come up with anything. Any ideas?

Edit: I forgot to mention the most important part. The percentages will for the most part be between 0.01% and 2.0%. So the average could be something like 0.42%, etc.