NEW YORK (AP) -- Independent bookselling remains on a roll.

The American Booksellers Association has grown for the seventh consecutive year, the trade group’s CEO, Oren Teicher, told the Associated Press during a recent interview. Core membership increased to 1,775, up by 63 over the previous year and by more than 300 since 2009. And with many stores opening additional outlets, the number of individual locations rose to 2,311, compared with 2,227 at this time in 2015 and just 1,651 in 2009.

With membership once well exceeding 3,000, independent sellers had been shutting down for decades, largely because of competition from Amazon.com and from the superstore chains Barnes & Noble and Borders. But Borders has gone out of business and Barnes & Noble is struggling. Independent booksellers also have benefited from the leveling of e-book sales and resilience of paper editions. According to Teicher, unit sales from some 580 stores reporting numbers are up 5 percent in the first four months of 2016 compared with the same period in 2015.

“I am thrilled and delighted to be able to tell you that our trend has continued and we had another really strong year,” Teicher said.

Optimism has become self-fulfilling. A decade ago, longtime store owners struggled to find successors because independent bookselling seemed so risky. Now, transitions happen routinely, with recent examples including Dudley’s Bookshop Cafe in Bend, Oregon, and Women & Children First in Chicago. While for years new stores rarely opened, they now do so frequently, with some of the owners including such writers as Judy Blume and Jeff Kinney.

Teicher did mention a couple of potential “clouds” in the future. With the economy recovering, real estate prices in many areas are going up and booksellers could face punishing increases in rent when their leases run out. Teicher also cited the initiatives nationwide to raise the minimum wage to as high as $15. Many booksellers are political liberals who favor the increases in principle, but in practice they will end up paying more. Teicher says a significant hike in salaries could mean the difference between a store making money or at best breaking even.

“We’re in a low-margin business, and that upward pressure on wages is a big deal,” says Teicher, adding that a traditional solution for retailers is complicated for bookstores.

“Someone might tell you, ‘Well, you know, do what the supermarket does and charge a quarter more for milk. Pass on the increases to the consumer.’ But as long as publishers continue to print the suggested retail price on the product, it’s hard to put a surcharge on it. It puts us in a peculiar position.”

Teicher speculated on a variety of options: “Increase efficiencies” in the supply chain, tax breaks to offset wage hikes, the removal of price stickers from books and deeper discounts from publishers.

And maybe, he says, publishers will raise the cost.

“It would not surprise me if there’s some upward pressure on prices,” Teicher said.

Publishers have advocated higher e-book prices as a way of helping printed books and physical stores remain viable, a stance that has led to fierce clashes with Amazon.com and an antitrust suit filed in 2012 by the federal government that led to multimillion dollar settlements. Understandably, they are at most non-committal about making traditional books more expensive.

“The truth is how much books cost is not specific to the minimum wage,” said Heather Fain, senior vice president and director of marketing strategy at Hachette Book Group. “It’s something we talk about all the time, especially in relation to print versus electronic prices.”

The latest ABA numbers arrive on the eve of BookExpo America, the industry’s annual trade show, which takes place this week in Chicago after being in New York since 2009. For the third straight year, BookExpo will be immediately followed by the fan-oriented BookCon. Featured authors at Chicago’s McCormick Place will include Veronica Roth, Sebastian Junger and Dav Pilkey of “Captain Underpants” fame, while panel discussions will range from the role of public libraries in the book industry to marketing through Facebook and other social media.

BookExpo America once routinely changed locations, but major publishers have grown used to the New York setting and the savings of not having to travel. Brien McDonald, the event director for BookExpo and BookCon, said BookExpo’s floor space at McCormick Place will be 11,732 square meters, a drop of nearly 20 percent from last year. BookCon, meanwhile, is expanding from 3,879 square meters in 2015 to 5,713 square meters.

Hachette, Simon & Schuster, HarperCollins and others based in Manhattan are sending fewer people than in previous years and none of the featured authors approach the star power of such past convention speakers as former President Bill Clinton, former Secretary of State Colin Powell and Barbra Streisand.

“We will have a smaller contingent and a smaller booth, which is a reflection of looking at the show and what‘s important about it,” Fain said. “You want to have a place to meet with the booksellers and you want to have a way to elevate the titles you’re focused on. But you don’t have to have a lot of people to do it.”