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.
The population density in the United States is 36 per Km2 (92 people per mi2). The total land area is 9,155,898 Km2 (3,535,111 sq. miles) 82.9 % of the population is urban (270,683,202 people in 2017) The median age in the United States is 38.1 years.