Population measures provide insight on the changing size and face of communities, and an area's needs and assets. For example, areas with large or growing populations of seniors or children may face challenges in providing needed services and generating enough tax revenue to support those services.

The population of the three-county MetroWest region has been aging. The number of people between the ages of 60 and 84 increased 31% between 2008-12 and 2018-22. The population 85 and older grew 10% during the same period. By comparison, the population 40 to 59 decreased by 4%, the population 20 to 39 grew 13%, and the population under 20 decreased by 1%. Since 2008-12, people between 20 and 39 overtook those 40 to 59 as the largest single age group in the region (885,100 residents, compared to 856,600).

One of the most dramatic age shifts in a particular locality has been in Wayland, where those aged 20 to 39 increased 58% and those under 20 did not changed. Millis (83%), Groton (76%) and Hopkinton (73%) saw significant increases in people between 60 to 84. In addition, Walpole had growth of more than 19% in the under-20 category.

The multi-year figures are from the Census Bureau's American Community Survey. The bureau combined multiple years of responses to the survey to provide estimates for smaller geographic areas and increase the precision of its estimates. The survey provides data on characteristics of the population that used to be collected only during the decennial census. Data for this indicator are expected to be released in the fourth quarter.