Support for former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE has hit record low of 26 percent, according to a new Hill-HarrisX poll released on Thursday.

That figure marks a one-point decrease from the previous Oct. 21-22 poll, and a 9-point decrease from his all-time of 35 percent in June.

However, the former Vice President still maintains his lead over progressive candidates Sens. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) and Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.), who have traded spots in recent weeks.

Warren slipped from 19 percent to 15 percent in the latest survey, but maintained her spot in second place, with Sanders trailing behind 14 percent.

Sen. Kamala Harris Kamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE and South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE are tied for fourth place, each receiving 6 percent support.

Sen. Amy Klobuchar Amy Klobuchar3 reasons why Biden is misreading the politics of court packing Social media platforms put muscle into National Voter Registration Day Battle lines drawn on precedent in Supreme Court fight MORE (D-Minn.) followed with 3 percent support, while both Sen. Cory Booker Cory Anthony BookerThe movement to reform animal agriculture has reached a tipping point Watchdog confirms State Dept. canceled award for journalist who criticized Trump 3 reasons why Biden is misreading the politics of court packing MORE (D-N.J.) and Former Housing and Urban Development Secretary Julián Castro drew 2 percent.

Every other candidate in the 2020 race polled at 1 point or less.

Meanwhile, the number of voters who are unsure about which candidate should be the nominee increased slightly from 13 to 16 percent.

The survey comes as a number of 2020 Democratic contenders gear up for the presidential primary debate in Atlanta.

Rep. Tulsi Gabbard Tulsi GabbardRepublicans call on DOJ to investigate Netflix over 'Cuties' film Hispanic Caucus campaign arm endorses slate of non-Hispanic candidates Gabbard says she 'was not invited to participate in any way' in Democratic convention MORE (D-Hawaii), who among the candidates polling at 1 percent in the latest Hill-HarrisX poll, became the latest candidate to qualify for the Nov. 20 debate.

Gabbard made the stage after receiving 3 percent support in a Quinnipiac University poll focused on Iowa that was released on Wednesday. She will join Biden, Warren, Sanders and Buttigieg. Businessman Tom Steyer Tom SteyerTV ads favored Biden 2-1 in past month Inslee calls Biden climate plan 'perfect for the moment' OVERNIGHT ENERGY: Trump administration finalizes plan to open up Alaska wildlife refuge to drilling | California finalizes fuel efficiency deal with five automakers, undercutting Trump | Democrats use vulnerable GOP senators to get rare win on environment MORE and tech entrepreneur Andrew Yang Andrew YangBiden's latest small business outreach is just ... awful Doctor who allegedly assaulted Evelyn Yang arrested on federal charges The Hill's Campaign Report: Biden weighs in on police shootings | Who's moderating the debates | Trump trails in post-convention polls MORE are also poised to take the debate stage.

To qualify for the debate this month, candidates have to accrue support from at least 165,000 unique donors and resister at least 3 percent in four qualifying polls or 5 percent in two early state polls by Nov. 13.

—Tess Bonn