Dramatic changes began in the 18th century. Life expectancy in England rose to 41 years by 1820, 50 years early 20th century, and 78 years today. A similar shift took place in all developed countries. The drop in mortality rates was particularly radical among children 1). This was because of the near eradication of deaths from infectious diseases- formerly the most common cause of death, since the young are most likely to get infections.