I have a table 30 rows, 3 columns

Col A is product name (3 products)
Col B is region name (US)
Col C is # Unit for each product (5)

Example

Cars US 5
Trucks US 3
Cars Europe 6

How create a formula that will give me the average number of units for the
sum of the products in a given region.

Output in example should be (5+3)/2 =4.5

Thanks.