Reads in the raw Zillow data, cleans up variable names and types, reshapes it to long form, and calculates an annual average from the monthly data.
process_zillow_data(file_path)| file_path | A character string with the path to the raw data.  | 
    
|---|
A data frame with the annual average rent by zip code.
zip: zip code (character)
year: year (integer)
annual_mean_rent: average annual Zillow rent index (numeric)
build_coc_zillow_rent() for creating the CoC level Zillow rent
index, build_tract_zillow_rent() for creating the census tract level
Zillow rent index