A study of 4,474 workers in a Chicago neighborhood in 1919 showed that about one in four was sick for a week or longer each year; on average these workers lost $119 or V3.7 percent of their annual wages. The proportion of families that could not "make ends meet" increased to 16.6 percent among those with serious illness, compared to 4.7 percent among those without. Sickness was the leading immediate cause of poverty and the chief factor in a quarter to a third of the charity cases in the state of Illinois.

Source: Paul Starr, The Social Transformation of American Medicine (New York: Basic Books, 1982), p. 245.

Sources:

James Bordley III and A. McGehee Harvey, Two Centuries of American Medicine, 1776-1976 (Philadelphia: W. B. Saunders, 1976);

Paul Starr, The Social Transformation of American Medicine (New York: Basic Books, 1982).