Average if cells are duplicates

Hi,

I have data based on zipcodes and these zipcodes fall into larger area codes. I would like to have this data as an average for each area. Basically I want all my data in new columns if areacodes match. I already have a seperate column for all the unique areacode used in my research. Presumably I would use the 'averageif' function but I do not know how to write that I want duplicates to average as a criterea. In the attachment I have made an example of what I need. What is the best way to get this average data in column 'H' and 'I' in my example?