With less than two months until the general election, Donald Trump has opened up an eight-point lead over Clinton in Iowa, according to a new poll out Thursday.

The Monmouth University survey found that likely Iowa voters backed Trump 45 percent to Clinton’s 37 percent, a greater edge than the billionaire had back in July, when he was up just two points. Eight percent of likely voters support Libertarian nominee Gary Johnson, while two percent are supporting the Green Party’s Jill Stein.

Trump’s added edge has come out of his support from independents, where he leads Clinton 44 percent to 29 percent. His lead among independents in July was 39 percent to Clinton’s 35 percent. Among Republicans, Trump gets 81 percent of their support. Ninety-one percent of Democrats, in contrast, support Clinton.

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According to the Monmouth poll, both candidates are held in poor esteem by Iowa voters, after contentious general election campaigns plagued by charges of racism and federal investigations. Fifty-five percent hold an unfavorable view of Trump, compared to 32 percent that have a favorable opinion. For Clinton, 58 percent hold an unfavorable view of the former secretary of state, while just 30 percent have a favorable opinion.

In the race for U.S. senator in Iowa, Chuck Grassley, the state’s six-term incumbent Republican senator, remains the odds-on favorite to win. He holds a double digit lead over former Lt. Gov. Patty Judge, the Democrat in the race: 56 percent over Judge’s 39 percent.

The Monmouth University Poll was conducted from Sept. 12-14 with 404 Iowa residents likely to vote in the November election. The survey has a margin of error of 4.9 percent.