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 of the United States was estimated to be 275,562,673 in July 2000. Females slightly outnumbered males and there were 0.96 males for every female in the population. This phenomenon is most pronounced among the elderly and is partially the result of longer life spans for women.