This project leans heavily on census.ire.org and attempts to calculate a diversity index for each county subdivision, i.e. town, in N.J.
It might be possible to extend the method to other states.

Two files are hard-coded into the outer script, DiversityCalc:
all_050_in_34.P1.csv and all_060_in_34_combo.csv

The first was downloaded from http://census.ire.org/data/bulkdata.html with 
   state=New Jersey,
   Summary Level=County
   Table = P1. Total population

It's used solely to assemble a table of the county names.

The second file (all_060...) was created in Excel.
It results from downloading two tables from the IRE bulk data page. 
Those tables are P3. RACE and P4. HISPANIC OR LATINO ORIGIN at the county subdivision level.
The combo sheet was created by pasting the p4 cells alongside the p3 table and verifying that the town names matched up.