Levene enrolled at Columbia University and in his spare time conducted biochemical research, publishing papers on the chemical structure of sugars. In 1896 he was appointed as an Associate in the Pathological Institute of the New York State Hospitals, but he had to take time off to recuperate from tuberculosis.
This graph shows the median age of the resident population of the United States from 1960 to 2015. In 2015, the median age of the United States population was approximately 37.7 years.
In contrast, the median age for the U.S. as a whole ticked up from 37.5 years to 37.6 years. These estimates examine population changes among groups by age, sex, race and Hispanic origin nationally, as well as all states and counties, between April 1, 2010, and July 1, 2013.