While there are more than enough mobile apps to go, the frequency in which they’re used isn’t as frequent as most companies hope, according to a new report from Millward Brown Digital.

First reported by eMarketer, a study conducted back in August indicates that there’s a serious lack of engagement with smartphone apps. Interest usually dips after the first 24 hours of install. The survey shows that 43% of smartphone owners in the U.S. use four to six apps on an average day. Considering they have between 40 to 70 installed per device, that’s a pretty small count.

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The study also shows that 72% of smartphone owners delete an apps due to lack of use. Other reasons for removal include an app’s battery drain, or freeing up memory space.

Another study, conducted by Appsflyer in July 2015, took a closer look at engagement, and how useful it is for app marketers. Looking over 450 million installs across all of eCommerce, the report indicates that engagement drops for both iOS and Android devices after that 24 hour period, with only 3.3% of Android users and 3.2% of iOS users using an app afterward.

Organic app acquisition plays a big part, according to the Appsflyer’s report. Retention rates on Android devices after a month’s time (30 days) shows 156% greater for organic app installs than paid app installs. The chart below breaks it down even further, for both Android and iOS. As you can see, there’s quite a drop off over a period of time – which could be alarming news for marketers that rely on app success.

Now it’s just a matter of finding a solution to this problem by looking into apps that keep people around on the long-term. Social sharing applications, like Facebook and Snapchat, keep people coming back for more with a daily, even hourly, interactions. Free-to-play games like Candy Crush Soda Saga and Clash of Clans also have a high popularity rate, making big money for its producers as a result.

Will marketers find a way to keep their apps relevant It’s just a matter of time, but it never hurts to study the successes.