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.
TODAY IN THE UNITED STATES, 40.3 million Americans are age 65 and older, an estimated 13% of the population, according to the U.S. Census Bureau. And their number is expected to more than double to 89 million by 2050.