https://fivethirtyeight.com/datalab/elitist-superfluous-or-popular-we-polled-americans-on-the-oxford-comma/?ex_cid=538twitter

There’s been a lot of ink spilled on the Oxford comma, the comma that goes before “and” in a list of three or more things. Is it a grammatical must or an unnecessary blight? (You’ve seen the insufferable and ahistoric comic of JFK and Stalin dressed as exotic dancers.) Grammatical experts have weighed in, but what does the average American think?