That's a good question, the only thing I could find (and take it with a grain of salt) was that Trump spent $5 per vote compared to Clinton's $10 per vote if you assume all the money they raised was spent.
https://www.reuters.com/article/us-usa-election-spending/at-...It is interesting to think of campaign efficiency (or propaganda efficiency lol) as CPV (cost per vote) to make it parallel to advertising metrics like CPC and CPI.
