Joe Biden's campaign burn rate is one of the highest of any top-tier presidential primary candidate since 2008, in July through September spending 12.1% more than it took in and more than 30% higher than his chief rivals, such as Elizabeth Warren and Bernie Sanders, according to data analyzed by the Washington Examiner.

In the third quarter of 2019, covering July through September, Biden's campaign raised $15.7 million and spent $17.6 million. The only candidate with a higher spending deficit was California Sen. Kamala Harris, who raised $11.8 million and spent $14.5 million, a 122.9% burn rate.

Among Biden's most costly expenditures, aside from staffing, was the use of private jets, which ran him $924,000. Biden also spent over $230,000 on "fundraising consultants" and tens of thousands of dollars on ritzy hotels such as the Carlyle Hotel in New York City.

At the end of September, Biden's campaign had $8.98 million cash on hand, compared to Sanders, the Vermont senator who sits on $33.7 million, Massachusetts Sen. Warren at $25.7 million, South Bend, Indiana, Mayor Pete Buttigieg at $23.4 million, and Harris at $10.5 million.

Biden's campaign dismissed concerns that its spending was unsustainable after Tuesday night's Democratic debate in Ohio.

“I think that we have the resources that we need to run our race. I think at the end of the day, decisions about money — it’s more important how you spend the money than how you raise it. We have the resources that we need to continue to run our race. We’ve always said we think that this race is going to be a dogfight, and it’s going to go long," said Biden spokeswoman Kate Bedingfield Tuesday night in the post-debate spin room. "We’re building an operation that is going to, that is going to be sustained that, you know, we think we’re going to be able to communicate with voters that we need to communicate with. So, we are 100% confident that we have what we need to run our race.”

The only other candidate closest to Biden's burn rate was Buttigieg, who spent 96.3% of what he took in. Billionaire businessman Tom Steyer, who is virtually funding his entire campaign, had a 94.8% burn rate.

For comparison, Barack Obama in the third quarter of 2007 ran a 100.9% burn rate in his successful Democratic primary fight against Hillary Clinton. In the third quarter of 2011, future Republican nominee Mitt Romney ran a 86.6% burn rate.

More discouragingly for Biden, his campaign's current burn rate closely echoes the 2007 fundraising number of Republican candidate Rudy Giuliani's, who brought in $11.6 million and spent $13.3, a 114.7% burn rate.

At the time, Giuliani was the front-runner of the GOP. The former New York City mayor held double-digit leads over his Republican opponents. But his campaign soon fell apart, as the former New York City mayor skipped early voting states such as Iowa in favor of Florida, weeks later. He soon dropped out, with Arizona Sen. John McCain claiming the Republican nomination in 2008.

Biden's fundraising report, which like all 2020 candidates was due with the Federal Elections Commission by the end of Tuesday, also shows top donors are growing skittish over his chances to pull out a win. In the second quarter, covering April through June, Biden raised $22 million and refunded $540,000 of that to donors at a 2.5% rate.

This latest quarter, however, Biden refunded $836,000, or 5.3%. Of that, 156 individuals received back their $2,700 donation. Warren's refund rate during her entire presidential run was only 0.4%.

And Biden raised relatively paltry amounts from supporters in early voting states. Biden raised $59,541 from Iowa residents and $46,479 from New Hampshire residents.

Recent surveys have shown a precipitous drop of support for Biden's candidacy among Democratic voters. In Iowa, Warren leads Biden by over 3 points in an average of recent polls. Multiple surveys released last month show Warren pulling ahead in New Hampshire as well. A September poll of Nevada voters showed Biden tied with Sanders.

— Emily Larsen contributed to this report.