New Hampshire’s Inverting Age Pyramid

May 24, 2012

Table Showing Composition of New Hampshire's Population by Age Group July 1, 2011

The U.S. Census Bureau recently released new data showing state and county population by major age groups as of July 1, 2011. This new data shows another slice of “Demographic Winter” in New Hampshire by looking at the overall age pyramid of the state. A healthy age pyramid, as the name suggests, is one where young folks form the large base and the oldest folks form the narrow top.

However, as we blogged previously, New Hampshire has  seen a steep drop in births in the state and three counties actually have more deaths than births. As a consequence, we would expect the percentage of folks under the age of 18 to become a smaller share of the population and those folks over the age of 65 to become a larger share. This new data confirms this.

As shown in the table above, as of July 1, 2011, 21.2 percent of New Hampshire’s population is made up of folks under the age of 18 (the 45th largest in the country) while 14 percent is made up of folks over the age of 65 (the 23rd largest in the country).

The rankings, especially for those over the age of 65, may not seem so bad until you  consider the sensitivity to an increase–a 0.5 percentage point increase in the “under 18″ group would only improve New Hampshire’s ranking by a mere two spots (to 43rd) while the same increase for the “over 65″ group would jump the ranking by 11 spots (to 12th).

Additionally, the data shows that two of New Hampshire’s counties already have an inverted age pyramid–Carroll and Coos. In Carroll County, 18 percent of the population was under the age of 18 while 21.4 percent of the population was over the age of 65–a deficit of 3.4 percentage points. In Coos County, 18.2 percent of the population was under the age of 18 while 20 percent of the population was over the age of 65–a deficit of 1.8 percentage points. Not surprisingly, both counties have more deaths than births.

Grafton County is likely the next county to suffer under an inverted age pyramid. Grafton has the smallest population of “under 18″ in the state at 17.9 percent with those “over 65″ making up 16 percent of the population–a small positive difference of 1.9 percentage points.

Hillsborough County has the healthiest age pyramid in the state with a population of “under 18″ at 22.9 percent (the highest in the state) and a population of “over 65″ at 12.2 percent–a positive difference of 10.7 percentage points.