Republican presidential nominee Donald Trump has seen a groundswell of support from black voters over the last week, according to the results of a tracking poll released over the weekend.

Democratic nominee Hillary Clinton experienced a nearly 20-point decrease in support from the same demographic between Sept. 10-16 according to the poll, which was conducted by the Los Angeles Times and the University of Southern California. The survey found Trump's support from black voters increased from 3.1 percent to 19.6 percent over the period, while Clinton's declined from 90.4 percent to 71.4 percent.

The reported shift spanned Clinton's collapse during a 9/11 ceremony in New York City, the revelation she had attempted to conceal a bout of pneumonia, and Trump's Sept. 16 revival of the "birther" issue, when he said Clinton was responsible for creating questions about whether President Obama had been born in the United States.

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The change in support fueled an overall increase of six percentage points for Trump in the survey. Trump led by nearly seven points among voters nationwide as of Saturday, 47.7 percent to 41 percent for Clinton.

"It's the largest shift we've seen in a one-week period since we began polling in July," said Dan Schnur, director of USC's Institute of Politics.

The RealClearPolitics polling average, which includes surveys dating to Sept. 5, shows Clinton leading by less than one percentage point nationwide.