After decades during which employers usually held the upper hand, something feels different in the U.S. labor market. Wages are rising across the income spectrum. Workers are quitting in huge numbers. McDonald’s franchisees are offering hourly workers child care and college tuition.

The COVID-19 pandemic and the unprecedented government aid in response to it are clearly part of the explanation for this, but it may also be relevant that the working-age population stopped growing a couple of years ago.

Definitions of "working-age” vary. In Bureau of Labor Statistics lingo it means everybody 16 and older, while international statistics-keepers such as the Organization for Economic Cooperation and Development and World Bank tend to define it as ages 15 through 64. I think the metric I’ve chosen — ages 20 through 64 — better reflects who’s actually available to work in the U.S., given that it includes every age group with a labor-force participation rate above 50% and excludes all those for which it is lower.