New England is looking a bit grayer than it once did. The region is now home to the top three states in the nation with the oldest median populations. The median age of residents in Maine is 44.6 years old, according to newly released U.S. Census Bureau data, the highest median age in the nation. New Hampshire residents are the second eldest, with the median resident 43 years old. Vermont came in a close third at 42.7 as the median age. The nation's population is, on average, older and more diverse than it was in 2000, according to the U.S. Census Bureau. The nation's median age rose from 35.3 years in 2000 to 37.9 in July of last year, the most recently available data. Massachusetts came in a bit below the nation's average, with a median age of 37.6 years. Why the age change? Baby boomers. "The baby-boom generation is largely responsible for this trend," said Peter Borsella, a demographer in the Census' population division. "Baby boomers began turning 65 in 2011 and will continue to do so for many years to come." Americans age 65 and over grew from 35.0 million in 2000, to 49.2 million in 2016, growing to account for 15.2 percent of the total population. Utah currently holds the title for the lowest median age in the nation at 30.8 years, following distantly by both Alaska and the District of Columbia, both of which have an average median of 33.9 years.