Much is made of the economic effects of baby boomers retiring, but just as important is the coming-of-age of their children, the "echo boomers."

"There are more 26-year olds than any other age group," Torsten Sløk, Chief International Economist with Deutsche Bank Securities writes in a research note. "This wave of echo-boomers will over the coming years get jobs and get married and increase their consumer spending."

Why it matters: The baby boomers came of age in the 1960s and 1970s—years that saw much faster economic growth than we have today. Millennials have been slow to acquire the trappings of adulthood like spouses, houses and children, but it's only a matter of time before they lean in to the sort of large purchases that can power a consumer-led economy.