How can I run through existing data already in a form (100's of records), and update a field value based upon some criteria?

 

For Example,

 

In Sample Employee Manager application, and the Add Education Details form...

 

how can I set the Percentage to 100% for all records where the the Year of Graduation contains a date (not blank).

 

I'm sorry to bother you.  I'm still learning if you offer action queries or if we need to use code to make such changes.

 

Thanks, ppD