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.
United States Population (1950 - 2017) Yearly Population Growth Rate (%) The current population of the United States of America is 326,002,603 as of Thursday, April 20, 2017, based on the latest United Nations estimates. the United States population is equivalent to 4.34% of the total world population. the U.S.A. ranks number 3 in the list of countries (and dependencies) by population.