What's the difference between i.e. and e.g.?
1530s, "a fixing of rates," verbal noun from rate (v.2). Meaning "a classification according to rates" is from 1764. Ratings of TV programs, originally radio programs, began 1930 in U.S. under system set up by U.S. pollster and market researcher Archibald M. Crossley (1896-1985), and were called Crossley ratings or Crossleys until ratings began to be preferred c.1947.