The iPhone's share of global smartphone app downloads stood at 29% in the second quarter of 2012, significantly below the 47% attributed to Android smartphones.
New market data from ABI Research suggests that the power of Apple's once-dominant smartphone is waning. Even the arrival of the iPhone 5 may cause only a temporary resurgence for the iOS smartphone.
Senior analyst Aapo Markkanen said: "The iPhone's download share tends to see a lot of seasonal fluctuation, but over the past year or so it has stayed surprisingly resiliently between 30% and 37% of the total.
"In our estimates the second quarter represented the first time the iPhone dipped below 30%. The iPhone 5 will most likely cause a second-half hike to the download count, but that may be of a rather temporary nature."
However, the main reason for this declining market share could be Apple's clampdown on download bots earlier this year.
Previously some iOS developers used download bots to manipulate their iTunes charts positions.
For example, app-marketing firm Fiksu has published data indicating that at the high end of the download chart the bot squeeze may have alone wiped off a quarter of daily volumes of iPhone apps.
For Android, the bots haven't been as big a factor to begin with, owing to Google's different app-ranking methods, as well as to the fact that in its app economy there is still far less money changing hands than on iOS.
As another reason Markkanen points to the growing prominence of the iPad. He added: "It's notable that among the iOS apps the momentum is also shifting up the value chain and towards iPad applications, and this change is happening definitely faster than what Google is experiencing.
"We estimate in the first half of this year the iPad saw over five times more app downloads than all Android tablets combined."