WASHINGTON (Reuters) - The most likely book readers in the United States are high-school students, college-age adults and people in their 30s, with e-book use highest among 30-somethings, a survey released on Tuesday showed.

Seventy-eight percent of Americans had read at least one book in the previous 12 months, with the rate 83 percent among those aged between 16 and 29, according to the survey by the Pew Research Center's Internet and American Life Project.

The survey is part of Pew's effort to assess U.S. reading habits as e-books change the reading landscape and the borrowing services of libraries.

The highest percentage of readers by age was 88 percent, among the 18-24 age group, followed by 86 percent in the 16-17 range. Readers in the 30-39 group trailed at 84 percent.

The lowest percentage of readers was among people older than 65, at 68 percent. The survey covered books in print, in electronic formats and audiobooks.

Among Americans who read e-books, those under 30 are more likely to read them on a cell phone, at 41 percent, or on a computer (55 percent) than on an e-book reader (23 percent) or tablet (16 percent).

Forty-seven percent of younger Americans read long-form e-content such as books, magazines or newspapers. But the highest e-book use was among people 30 to 39, at one quarter.

The findings were the result of a phone survey of 2,986 people aged 16 and older conducted between November 16 and December 21. The margin of error is 2.2 percentage points.

In a separate May 2012 survey, 60 percent of respondents under 30 said they used a library in the past year.

"Many of these young readers do not know they can borrow an e-book from a library, and a majority of them express the wish they could do so on pre-loaded e-readers," the Pew report said.

The library survey was done online, with 6,573 people answering at least some questions and 4,396 completing the questionnaire. No margin of error was given.