World population by age groups and sex: percentage of the total population in 1950, 2010, 2050, and 2100, respectively. (Data extracted from United Nations, Department of Economic and Social Affairs, Population Division (2011). World Population Prospects: The 2010 Revision.) Source: Chapter 16. Aging Populations and Chronic Illness, Understanding Global Health, Second Edition Citation: Markle WH, Fisher MA, Smego RA, Jr.. Understanding Global Health, Second Edition; 2014 Available at: https://accessmedicine.mhmedical.com/DownloadImage.aspx?image=/data/Books/mark2/mark2_c016f003.png&sec=46799397&BookID=710&ChapterSecID=46796917&imagename= Accessed: October 18, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved