Tired of hearing people grouse about a tuned-out, apathetic younger generation?

Well, here’s a comeback: America’s young adults are more serious about giving back than their parents were.

In fact, those under age 30 now are more likely to say citizens have a “very important obligation” to volunteer, an Associated Press-GfK poll finds.

The embrace of volunteering is striking because young people’s commitment to other civic duties — such as voting, serving on a jury and staying informed — has dropped sharply from their parents’ generation and is lower than that of Americans overall.

Among six civic activities in the AP-GfK poll, volunteering is the only one that adults under 30 rated as highly as older people did.

Today’s young adults grew up amid nudges from a volunteering infrastructure that has grown exponentially since their parents’ day, when the message typically came through churches or scouting.

In the decades since President George H.W. Bush championed America’s volunteer groups as “a thousand points of light” at his 1989 inaugural, the number of nonprofits has skyrocketed. The Martin Luther King Jr. holiday and Sept. 11 have become days of service. Individuals launch community projects through social media, instead of hanging posters and making phone calls.

Twenty percent of adults under 30 volunteered in 2013, up from 14 percent in 1989, according to census data analyzed by the Corporation for National and Community Service. It seems likely that the millennials’ volunteering rate will climb higher, because past generations have peaked in their 30s and 40s, when many parents give their time to schools, youth groups or community improvements.

“We’re on the crux of something big, because these millennials are going to take this spirit of giving and wanting to change communities, and they’re going to become parents soon,” said Wendy Spencer, chief executive of the Corporation for National and Community Service. “I am very encouraged by what we’re seeing.”

The vast majority of Americans believe citizenship comes with an array of responsibilities. But the strength of that conviction has weakened since the General Social Survey asked about obligations of citizenship in 1984.

Seventy-seven percent say reporting a crime you witness is very important, down from 90 percent three decades ago in the survey conducted by NORC at the University of Chicago. Three-quarters call voting in elections very important, about the same as in the 1984 survey, though only about 36 percent of eligible voters cast ballots in November’s midterms.