Uncovering and explaining how our digital world is changing — and changing us.

Apple recently announced that its iOS users alone have downloaded more than 140 billion apps since the App Store launched in 2008.

But the app market, as we’ve noted, is still a challenging one.

Half of all U.S. smartphone users download zero apps per month, according to comScore’s latest mobile app report.

Specifically, some 49 percent of U.S. smartphone users download zero apps in a typical month, according to comScore, reflecting a three-month average period ending this past June.

Of the 51 percent of smartphone owners who do download apps during the course of a month, “the average number downloaded per person is 3.5,” comScore’s report says. “However, the total number of app downloads is highly concentrated at the top, with 13 percent of smartphone owners accounting for more than half of all download activity in a given month.”

Do these concepts sound familiar? That’s because comScore has been banging this drum for a while. Two years ago, a similar study found that almost two-thirds of U.S. smartphone owners downloaded zero apps in a typical month. So this year’s 49 percent suggests an improvement.

What’s the deal? ComScore’s Andrew Lipsman says it’s more a reflection that his company has improved its methodology since then — rather than any drastic changes in the app economy — so it’s not fair to compare the two surveys apples-to-apples.

Meanwhile, others report significantly different data. Tune, a company that works in the mobile-app advertising market, found that 75 percent of U.S. smartphone owners download at least once a month, based on a June 2016 survey.