1927
In 1927, 40,000 public penny scales were dispersed throughout the US and earned $5 million dollars for the public scale industry. Although the public penny scales were first introduced into the US in the latter part of the nineteenth century, their popularity by the end of the twenties, as Schwartz suggests, "reflected a growing belief that you should know your own weight".
Schwartz, H. (1986) Never satisfied: a cultural history of diets, fantasies and fat. Free Press