AUGUSTA – Newly released analyses of census data paint a portrait of a graying Maine population that will have fewer people entering the labor market in the years ahead.

The number of Maine residents older than 44 increased by 122,600 from 2000 to 2010, while the number under age 45 decreased by 69,100. The figures point to a tide of baby boomers, people born in the years from 1946 to 1964, who are moving across the demographic landscape. Many are expected to retire in the next two decades, according to the state Department of Labor.

“An aging, slowly growing population and the declining rate of residents participating in the labor force will result in slow labor force growth during the coming years,” the department said.

Between 2000 and 2012, the labor force grew older as the population aged and work participation rates for younger workers declined, the department’s Center for Workforce Research and Information said. Currently, 46 percent of private industry workers are at least 45 years old. Within the next 20 years, at least 40 percent of the current work force for most sectors will be 65 or older, the center said.

“No county will escape the demographic challenge posed by the aging work force. Even in Cumberland County, which has the youngest work force, 22 percent are 55 years of age or older and 46 percent are 45 or older,” the report says.

An analysis of U.S. Census data by the state Governor’s Office of Policy and Management says Maine is tied with Vermont for the smallest percentage of residents under 18 years old, 20.7 percent. It also says Maine has the nation’s highest percentage of baby boomers at 29.4 percent, and the oldest median age, 43.

The analysis also shows that Maine’s birth rate of 14.1 per 1,000 women in 1990 slipped to 10.2 in 2010.