The results were released by the Harris Poll as part of its quarterly "Tech Tracker" measuring technology ownership and use among U.S. adults.
While Android smartphone ownership rose to 30 percent, up 4 points since April, iPhone ownership at 2 percent showed less movement, up just 1 point since April, a release from Harris Interactive reported Thursday.
And although the iPad still rules tablet category overall, Samsung and Google are the brands helping the category grow, the poll found.
With nearly four in 10 Americans owning a tablet, Apple iPads account for a strong percentage of the category, yet show little movement, Harris Interactive said.
The iPad series, at 17 percent, is up only 1 point from April.
Samsung's Android-powered Galaxy series of tablets, which doubled its ownership figures from April, from 3 percent to 6 percent, appears to be the product line most notably contributing to category growth, the poll found.
The Harris Poll surveyed 2,242 adults online July 17-27.