From 1976 to 1980. People's income more than quadrupled, with the largest paid audience of any American magazine. By 1991. it was the most profitable magazine in the world. And thus the most valuable. So it has remained ever since, (By the 2010s, a full-page advertisement in People was running about $350,000. as compared to a mere $12,000 for an advertisement in Harpers, or about $160.000 for a full-page advertisement in The New York Times newspaper.)
Tim Wu "Attention Merchants" (2016)