Percentile function in VBA, Excel

I urgently need help to write a VBA code that does the following: I have a list of material numbers. Each material number appears several times in the list (the list is sorted, so all the material numbers that are the same are grouped under another) and next to the material number is a lead time. I want the code to give me the 80th percentile of the lead time of a specific material number.

Please see the attachment of what i want the code to do.