An examination of this population pyramid reveals peaks and valleys. Why do the age groups have different size populations? Let’s examine the baby boom generation (50- to 69-year-old population). During the baby boom, the U.S. population rapidly grew because of high fertility rates following World War II. This population surge is reflected in the U.S. population pyramid as an outward bump in those baby boomer age groups. As the baby boomers grew up, many had kids of their own. The children of these baby boomers, frequently called the echo boomers or millennials, can be seen as a similar bulge in the 15- to 34-year-old population. Even with lower fertility among baby boomers compared to their parents’ generation, the birth of the millennials still represented a mini population boom, simply because there were so many potential boomer parents.

Looking at the U.S. population pyramid, we also see how noticeably larger the older female population (age 80 and over) is when compared to the male population at the same ages. This size differential stems from the fact that, generally, women live longer than men do. As a result, older women tend to outnumber older men. Women’s higher share of the older population is one of the more consistent features in almost all population pyramids, regardless of region or level of geography.

Nothing really stellar to quote as a sample of the article. The charts are where it's at. Especially the sample cities.