The results include 25 percent saying that the billionaire businessman was "very likely" to be the nominee, according to the Rasmussen results released Friday.
Rasmussen surveyed 1,000 adults Wednesday and Thursday for its latest weekly survey. It has a margin of error of 3 percentage points.
The results compared with 27 percent who felt that Trump's nomination was likely shortly after his June 16 announcement, including only 9 percent who said it was "very likely," according to Rasmussen.
"Donald Trump has captured the public’s attention for better or worse, and his bid for the Republican presidential nomination in 2016, once seen as a pipe dream, is now a topic of serious discussion," Rasmussen said in announcing the latest poll results.
