Delivery Schedule Percentage

I'm trying to run a spreadsheet for Vendor Deliveries and got as far as promised delivery date and actual delivery date with a late or on time comment. Im trying to get a percentage from this data. Can someone help me with this!!? Please see the excel spreadsheet that i have uploaded. Delivery Schedule.xls

Not getting anything. Do i just enter that information into a blank cell below the column?

I appreciate the help but im not much more than a beginner with excel and really dont quite understand what you just did. Is there an easier way? What i also want to do is filter just a single vendor from a period of time and get the same percentage like as if it was all the vendors.