How to automatically update a % field according to a dropdown field in the Quote table

How to automatically update a % field according to a dropdown field in the Quote table

Hello there,

I have following couples:

Success %Status
0%NP
30%No Feedback
50%PR
80%Opp. Concreta
100%A

I would like the Success % field (percent) to automatically update based on the item of the Status field (dropdown). The fields are within the Quote table. 

Could you please help me build the right function to get what I need?

Thanks!

Valeria