Donald Trump's running mate is less popular with American voters than Sarah Palin was as she ran alongside Sen. John McCain, polls and analyses show.

FiveThirtyEight, an aggregator of national polls, found this week that Vance's net favorability has plummeted six points from -3.3 percent on July 18 to -9.3 on Wednesday, Aug. 14.

A New Republic analysis declared Thursday, "Vance is possibly the least popular vice presidential candidate of the 21st century."

Vance's unfavorably numbers jumped more than 13 points in less than a month, with 28.9 percent of voters viewing him poorly in a July poll but 42.4 percent feeling the same way in August, according to the analysis.

The number of voters who view Vance favorably increased only 7 points from 25.6 in July to 33.1 percent in August, FiveThirtyEight reports.

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The increase in both numbers reflects Vance's growing exposure as the Republican nominee running alongside Trump, the New Republic argues.

The outlet blamed gaffes and questionable claims about cat ladies and childless Americans for the increase in unfavorable polling.

"As a result of his botched rollout, which included widespread backlash for his egregiously sexist comments and low-energy speaking events marred by gaffes, Vance’s net favorability dropped even lower," the analysis states.

"Vance is officially less liked than Sarah Palin, who is widely regarded as one of the least popular vice-presidential candidates in recent history," according to ABC News.

Vice President Kamala Harris' running mate Gov. Tim Walz (D-MN) has also seen his favorability drop, the data showed. As of Wednesday, he had a net favorability of 4.7 percent, 14 points above Vance's.