Population data released Thursday by the U.S. Census Bureau continues to paint a portrait of Maine as a graying state lacking in diversity.

At a time when millennials outnumber baby boomers nationwide, Maine saw the largest increase in median age of all states – 43.9 to 44.2 from 2013 to 2014. There is now a nearly 13-year difference between the median ages in Maine and Utah, the state with the lowest median age at 30.5, according to Census data. Maine saw a modest 0.12 percent gain in population, with most of the growth coming in southern and coastal counties. Maine’s population grew from 1.328 million to 1.33 million from 2013 to 2014, according to Census data.

Maine is second only to Florida in percentage of population over age 65, at 18.3 percent. In Florida, 19.1 percent of the population falls into the 65-and-older category.

Nationwide, the new Census data shows millennials – those born from 1982 to 2000 – now number 83.1 million and make up a quarter of the country’s population. There are roughly 300,000 millennials in Maine, or 22.6 percent of the population.

The high percentage of people in their 50s and 60s in Maine will create “significant” issues in the coming years as baby boomers retire and leave the workforce, said Glenn Mills, chief economist for the Maine Department of Labor’s Center for Workforce Research. He estimates the state labor force will shrink by 15,000 between 2012 and 2022.

“In the past, as people aged out of the labor force, there were more people aging into it,” Mills said. “Today we’re at a point where there are more people exiting the labor force. It’s not as easy for employers to replace those people.”

The American population as a whole has become more racially and ethnically diverse in the past decade. Nationally, millennials are more diverse than older generations, with more than 44 percent identifying themselves as members of a minority race or ethnic group. Among Americans younger than 5, for the first time more than half – 50.2 percent – are part of a minority race or ethnic group.

But that diversity is not reflected in Maine. The state has the highest percentage of non-Hispanic whites in the nation at 93.8 percent. Nationally, 62.1 percent of the population is white.

Mills said Maine’s lack of diversity contributes to its having the nation’s oldest median age.

“Birth rates have been plunging throughout the nation for all racial groups, but especially among white people,” he said. “That’s why the least diverse states have become the oldest.”

Seven counties – including Cumberland and York – gained population, while seven others saw their populations shrink. Lincoln and Piscataquis counties saw no changes in population. Maine is now one of only 10 states with more men than women.