Since Apple first launched its App Store six years ago, developers have uploaded more than 1.6 million apps, with nearly 60,000 apps added each month, according to a new report by a mobile analytics company called adjust.
With such a high number of apps available, how can developers make sure their apps are being discovered and downloaded? They can't, the report says -- resulting in hundreds of thousands of so-called "zombie apps," which are defined as "apps that are available, but appear to have no life in them."
To avoid being classified as a "zombie," an app must rank somewhere on any one of the nearly 40,000 Top Charts available multiple times during an evaluation period of one month.
In the latest evaluation, 80 percent of available apps were considered zombies. That's a total of nearly 950,000 apps.
The number of zombies has increased in recent years, the repot says. In June 2013, the total number of zombie apps in the store was 70 percent, and it rose to 75 percent by December 2013.
"As the App Store and the apps within it mature, more than ever it becomes essential for marketers to look at new techniques to re-engage existing users and get ROI. The report that we've released shows the development of the App Store and highlights the critical need for marketers to engage key audiences for ensuring the longevity and visibility of their app," Christian Henschel, CEO and co-founder of adjust, said in a press release.
Unlike the multitude of zombie apps, which go on living, a relatively small number of apps are considered officially dead, having been pulled from the App Store. Over the years, about 350,000 apps -- about 22 percent of the 1.6 million uploaded -- have been taken off the shelves across all categories: games, books, entertainment and others.