If you Population numbers are in column A and the zipcodes are in column B
then this will give you the Zipcode of the larges in your area(expand array
to suit)

=INDEX($A$1:$B$48,LARGE($A$1:$A$48,1),2)
This would find the second
=INDEX($A$1:$B$48,LARGE($A$1:$A$48,2),2)

and so on.

-John
"DEI" wrote:

I have a distribution of numbers (population totals) across 295 zip codes. I
would like to identify the zip code total that represents the "80/20" break
(the pareto principle - the assumption that 20% of the number zip codes
contain 80% of the population of the region).

I.e., I would like to enter a function that returns the zip code total that,
above which, the zip code totals comprise 80% of the population. This will
enable me to identify the number of zip codes that comprise 80% of the
population, comparitively small, with a COUNTIF function.

Is this possible.

Thanks,

DEI