The graph shows a steady increase in the life span of Americans born during the 20th century.
 
   Notice that the graph shows a trend of steady gains.  Many students and even adults often focus on short-term events, and lose the perspective of long-term trends.  For example, the development of penicillin was a great advance in medicine, but its actual impact on average life spans is far less than the gain from steady improvements during the century in nutrition, city water and sanitation, housing, etc.
 
   This graph is a good reminder that the trends that create progress and improvement in American life have been at work for a long time.

Making the chart, page 169

Background for the chart question, page 168

   The graphs on these pages do support the idea that the Progressive Era was a period of improving conditions for the average American. 
   In fact, the goals of the Progressives were just the kind of basic improvements that impact living conditions for ordinary citizens the most.  Clean water and clean streets, basic public health measures like pasteurized milk, job safety laws - these were all some of the measures pushed by Progressives.
 
   Even beyond specific laws and reforms, the Progressive movement spread the American attitudes toward progress and improvement that trace back to the earliest colonies. 
   Such attitudes, even when translated into the life of an American city like Chicago in 1900, created a broad and powerful social force to "make tomorrow better than today."  In countless ways, that spirit leads people to act in ways that improve their own lives, and the lives of those around them.

   There are certainly many factors that contributed to the fall  in infant mortality rates in American during the 20th century. 
   The most important was the general rise in the standard of living brought about by a growing economy.  Rising incomes means better food, better housing, heat in the winter, better access to medical care, and a host of other advantages.

   While the century did see some dramatic downturns in the economy, the overall trend for wages and business growth was steadily upward.  To understand the importance of this, consider that one economist has estimated that a steady two percent annual growth in the national economy will produce, over time, more benefit than all the government social welfare programs combined.
   The decades after 1900 also saw a dramatic improvement in medical knowledge and public health measures such as vaccinations.