Jamaica Plain is getting younger and younger. Or it seems that way to residents who have lived here for a while.

Although JP is diverse in terms of race, ethnic groups and incomes, the truth is that young adults have dominated the neighborhood’s economy and culture for more than 30 years.

Nearly one-third of residents in JP, about 12,000 people, are between the ages of 20 and 34, according to the 2010 Census, Summary File 1, Boston Redevelopment Authority (BRA) Research Division Analysis. And about 27 percent are between 25 and 35. That’s a huge lump of people in one small age group.

Don’t believe it? Next time you are in a store or restaurant or any public place in JP, look around.

Boston is the same and second only to Austin in its large proportion of young adult residents. The City of Boston created a nonprofit in 2004 called “One in Three” to serve the one in three Bostonians who are 20-34. Boston has been home to this large proportion of young adults since the 1970s, according to the BRA.

So, why do they come to Boston and, specifically, to JP? An easy answer is college. And it’s true that more than 1,000 college students—half undergraduates, half grads—lived in JP last year, according to reports from colleges.

But JP, obviously, has more going for it. The reasons young adults choose certain places to live are subjective. Attractions for young people—all of which JP has in plenty—include: a reputation for having lots of young adult residents, the arts and music scene, coffee shops, “coolness,” and seeming “hip,” according to “Sperling’s Best Places” and other researchers. The job market and housing costs are reportedly not major considerations.

Young adults in One in Three focus groups said the top reasons they chose Boston are: diversity; size; cultural and social scene; ease of getting around; character; and history. Jamaica Plain abounds in all of them.

The large number of young adults here keeps the neighborhood perpetually on the cutting edge. JP practically invented “hip.”

Young adults, One in Three points out, “possess significant discretionary income.” Less likely to be married or to have children, they tend to go out more. They help ensure that JP coffee shops have latte drinkers and that restaurants fill tables. They go to First Thursday and other local arts and community events.

In JP, it seems that the dominant age group has traditionally had a powerful effect on neighborhood organizations, politics and policies, ushering in new ideas and trends.

It’s no accident that, after intense lobbying and lots of volunteer effort by young adults, JP was the first Boston neighborhood, back in the 1980s, to get recycling. Bicycles pedaled our streets before they became as popular citywide as they are today. JP has advocated “shop locally” since the early 1990s.

JP benefits from a demographic circle: The neighborhood appeals to young adults who continue to make it appealing to everyone.