ABSTRACT
Perhaps the greatest of all human achievements has been the enormous increase of human longevity that has occurred over the past few centuries. The average length of life in the early history of our species was probably in a range of 20 to 35 years (Table 2.1). By the beginning of the 20th century, this value had risen already to around 50 years in industrialized countries. One century later, the world’s healthiest countries have a life expectancy at birth of around 80 years. Thus, around half of the historical increase in human life expectancy occurred during the 20th century. Of course, much of the increase in this average value has been due to the near-elimination of infant and childhood deaths. According to the available evidence, in the distant past, around a quarter of all babies died in their first year of life. Today, in the most advantaged countries, less than a half percent of infants meet a similar fate.
