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 nation as a whole grew nearly two years older since the last Census count in 2000, when the median age was 35.3. In 1990, it was just 32.7. The second oldest state is Vermont, with a median age of 41.5. West Virginia's median is 41.3 and New Hampshire's is 41.1. Seven states have a median age of more than 40 years. Florida did have the highest percentage of senior citizens -- residents aged 65 or older -- at 17.3%. That was well above the national median of 13%.