The entirety of all of the data for these trends is based on mentions in The New York Times. All of it. Transparently, yes. Note the caveat:
"If anything, given the paper’s New York-centric restaurant coverage, we might expect it to be a bit ahead of the curve relative to a broader sample of newspapers from across the country."
Which made me wonder, what other trends did The New York Times start? Using the same database of articles, I did a few analyses of my own.