RT Book, Section A1 Campbell, Edward J. A1 Kliment, Corrine R. A2 Grippi, Michael A. A2 Antin-Ozerkis, Danielle E. A2 Dela Cruz, Charles S. A2 Kotloff, Robert M. A2 Kotton, Camille Nelson A2 Pack, Allan I. SR Print(0) ID 1207825930 T1 Aging of the Respiratory System T2 Fishman’s Pulmonary Diseases and Disorders, 6e YR 2023 FD 2023 PB McGraw-Hill Education PP New York, NY SN 9781260473988 LK accessmedicine.mhmedical.com/content.aspx?aid=1207825930 RD 2025/03/18 AB The fastest growing segment of the U.S. population consists of individuals of age 65 and older. In the 2020 census, this segment comprised 57.8 million individuals or 17% of the population. Since the 1950s, the median age of the U.S. population has increased by 20 years.