Only a small fraction of the 2,000-mile wall President Trump vowed as a candidate to build on the U.S.-Mexico border has gone up since he took office more than two years ago, according to a document the defense agency overseeing construction provided to Sen. John Hoeven, R-N.D.

Exactly 39.8 miles of wall — technically steel bollard fence — have been installed along the southern border since January 2017, for an average of 1.7 miles per month.

"The Corps has told our office that they have completed construction on 39.8 miles using FY17 appropriations funding, and that additional projects using FY18 funding are underway," a representative for Hoeven's office wrote in an email to Washington Examiner.

However, earlier this month, the Defense Department agency overseeing construction told Trump 82 miles had been completed by his administration.

“We have put in the ground over 82 miles that is up to date. And then, right now, by the end of this year, we’ll have another 97 miles that will go in," Army Corps of Engineers Lt. Gen. Todd Semonite told Trump during a visit to Calexico, Calif., April 5.

The Washington Examiner asked the Army Corps to clarify how many miles of wall it has put up over the past 23 months, but the corps said only Customs and Border Protection could provide the figure.

CBP did not provide a number. The Department of Homeland Security and White House also did not share how many miles of barrier have gone up under Trump even though, publicly, Trump and his campaign have touted the progress they claim has been made on the project.

Trump's 2020 campaign debuted the slogan "Finish the Wall" at his first rally of 2019 in El Paso, Texas. At one point during his speech, the crowd began cheering, "Build that wall." Trump responded, "Now you really mean 'finish that wall' because we've built a lot of it."

Acting Homeland Security Secretary Kevin McAleenan echoed that sentiment earlier this week when he told NBC News the Trump administration was "aggressively" working to build the wall.

Although the campaign has made the border wall its main messaging line in the 2020 race, a spokeswoman could not confirm how many miles of barrier have been erected since January 2017.

"No President has been as strong, relentless, and unwavering on border security as President Trump," Kayleigh McEnany, national press secretary for the campaign, wrote in an email. "From an emergency declaration and a veto to withholding aid from countries that serve as an origin for the illegal immigration crisis we face, President Trump has made good on his promise to build the wall, secure the border, and protect the American people..."

Congress in 2017 approved 40 miles of new and replacement wall. By next month, those 40 miles of construction in San Diego, Calif.; Santa Teresa, N.M.; Calexico, Calif.; and El Paso, Texas, will be completed.

In the 2018 omnibus, lawmakers also approved around 70 miles of new and replacement wall in the Rio Grande Valley of Texas, various regions of California, and Yuma, Ariz. To date, less than one mile has been installed.

No other projects have been awarded with fiscal 2019 money that was approved in February though Semonite has claimed the Corps will put up 450 miles of wall in the next year and a half.

Hoeven said he has serious concerns with that claim. “Given the situation at the southern border, we need to secure the border. The construction process needs to be transparent, and the border wall built as efficiently and effectively as possible," he said.

Sen. Kevin Cramer, R-N.D., called last month for the Army Corps to be "fired" because it has "wasted taxpayer funds and been egregiously slow in constructing physical barriers" on the U.S.-Mexico border.

“The president prides himself on accomplishing projects on time and under budget. Unfortunately, current construction of the wall has been contracted out to the USACE, and on time and under budget has not characterized their work. Below are three specific examples of how the USACE has wasted taxpayer funds and been egregiously slow in constructing physical barriers on our southern border , " Cramer said in a statement at the time.

Roughly 700 miles of the 2,000-mile border has some sort of barrier as a result of the Secure Fence Act. Around 300 miles of that is a vehicle barrier that is less than four feet tall.