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 first decennial census in the United States showed a population of just under four million people. Today, the U.S. population is estimated at more than 310 million. Here you will find a list of the U.S. population every ten years from the first official census in 1790 to the most recent in 2000. 1790 - 3,929,214. 1800 - 5,308,483.