There may be over 1.2 billion apps in the App Store, but it appears most people are content to use the apps they've already downloaded.

A staggering 65.5% of U.S. smartphone users fail to download any new apps each month, according to comScore's recent mobile app report.

Even though people are using the apps they have more than ever, only approximately a third of U.S. smartphone users choose to give a new app a try, with this remaining third downloading an average of three apps per month.

It could be that people feel they already have a more than adequate arsenal of apps on their smartphone, and they're happy to use the apps they have. It makes sense, and ComScore's report highlights that tried-and-true favorites such as Facebook, YouTube, Google Play, Instagram, Pandora, and Gmail all rank among the 25 most used apps across all platforms.

But the issue could also be that it can be hard to discover new apps.

Apple's App Store is growing larger every day, and yet it's never been more difficult to connect the right user to the right app, a problem that is tied to how bogged down App Store search has become.

You can download and read comScore's full U.S. mobile app report over at their site.