While the oldest of the baby boom generation is just now hitting the age 65 threshold that has been a traditional line above which someone is considered elderly, within 15 years all of that large population cohort will be above that age, with important implications for the country, according to an analysis done for the government.

For example, it said the shift will result in a rise in the percentage of the population above that mark from 13 percent in 2010 to 19 percent in 2030, and a similar drop in the percentage between age 20 and 64—the traditional working age population—from 60 percent to 55 percent.

Meanwhile, the “dependency” populations—those above 65 or under 20 who traditionally are labeled as too young or too old to be in working careers—will rise slightly on the lower end from but substantially on the upper end.

Farther out into the future, the baby boomers also will change the makeup of the aged population, which consumes disproportionate amounts of services such as health care and nursing home care, and who represent continued drains on programs such as Social Security. Currently, about 14 percent of the population is 85 or older; in 2050, that proportion will rise to 21 percent.

Offsetting some of the effects of the aging boomer population will be population growth, some of it driven by immigration, says the report. The population aged 65 and over of the future will be more ethnically diverse and also more male, due to improvements in life expectancy for men that are narrowing the gap between women and men among that segment of the population.