• by Jack Loechner , Staff Writer @mp_research, July 7, 2014

 According to the MarktingCharts staff, in a timely analysis, marketers tend to focus a lot of energy on Millennials, but the report asks, “… so how many millennials are there in the US, anyway?” Their lives are deconstructed on many different levels, and there’s research to be found on anything ranging from their brand loyalty to their trust in user-generated content and their stance on social issues, says the report.

A study on Generational Theory points out that It is not where the birth cohort boundaries are drawn that is important, but how individuals and societies interpret the boundaries and how divisions may shape processes and outcomes. However, the practice of categorizing age cohorts is useful to researchers for the purpose of constructing boundaries in their work.

The Generational report puts Millennials, also known as the Millennial Generation, and "Generation Y", are the demographic cohort following Generation X. Commentators use birth dates ranging from the early 1980s to the early 2000s.[

Those analyses are all helpful in their own right, says the MarketingCharts staff, but stepping back to the big picture for a moment, how many of these prized individuals are there in the US?

Before putting out some numbers, there are a few problems to take note of, says the report, noting that there is no consensus definition of a Millennial. There are some widely accepted definitions of Gen X, Gen Y, and Gen Z, with Gen Y often interchanged with Millennials. It’s also worth noting that a young Gen Xer might feel more culturally similar to Gen Y. In other words, cultural and behavioral tendencies don’t tend to have fixed age breaks.

Nevertheless, marketers and researchers often look at age groups. So here’s a reference list of some commonly used age brackets and their corresponding population estimates and population shares as of July 1st, 2013.

The report leaves us with a few more population fun facts:

• As of July 1st last year, there were an estimated 67,347 centenarians (100+) in the US. More than 55,000, or about 82%, of them were female
• The median age of an American last year was 37.6, inching up from 37.5 the prior year. Median age was higher among females (38.9) than males (36.2)
• The number of Americans under 5 was fairly steady at just under 20 million, or 6.3% of the population
• The 65-and-older population grew by 3.6% year-over-year in 2013 to 44.6 million. The oldest Baby Boomers became Seniors
• The number of Americans aged 85 and older also grew by roughly 3% between 2012 and 2013

For more from MarketingCharts, please visit here.