I am working on getting a field that tracks the picklest values of another field. I want it to tell me what is the highest value that the picklist field has ever acheived. This is for a lead/contact field. In this example, I am tracking a lifecycle of a lead/contact.

My picklist values, in the order of achievement, are:

PROSPECT
INACTIVE FREE
FREE TRIAL
FREE ACTIVE
CUSTOMER BUSINESS
CUSTOMER PRO
CUSTOMER ENTERPRISE

Any help on this would be appreciated. I am currently tracking the field history of this field in both the contact and lead. 

Thank you in advance!

Kevin