WASHINGTON (Reuters) - Forty percent of the staff members who were working a year ago in U.S. President Donald Trump’s White House have since left for other jobs, a new report shows, providing a snapshot of the chaos among Trump’s closest subordinates.

FILE PHOTO: A combination photo shows former staff of President Donald Trump's White House who have since left for other jobs, top row L-R: Chief of Staff Reince Preibus, top economic adviser Gary Cohn, Deputy Chief of Staff Rick Dearborn, bottom row L-R: Staff Secretary Rob Porter, deputy national security advisers Dina Powell and K.T. McFarland in Washington, DC, U.S. from Reuters files. REUTERS/File Photos

At all levels of seniority and pay levels, Trump staff churn has exceeded that of the executive office of former President Barack Obama, with a noticeably larger turnover among top aides, according to an annual report on the White House payroll released late on Friday and reviewed by Reuters.

In the top tier of staff, Trump’s White House has so far had the highest turnover of any modern administration, said Martha Kumar, a Towson University political scientist emeritus.

GRAPHIC: Turnover in Trump's White House: tmsnrt.rs/2KBIcKZ

That hurts Trump’s ability to advance his policies in coordination with outside allies, said Kumar, director of the White House Transition Project, who has kept track of the turnover since the Reagan administration.

“You need to have a continuity,” she said.

The White House did not respond to requests for comment.

Fifty-six percent of the highest-ranking people in Trump’s White House named in last year’s payroll report have since left or have announced they will soon leave, including chief of staff Reince Priebus, top economic adviser Gary Cohn, deputy chief of staff Rick Dearborn and spokesman Sean Spicer.

The report, showing names, titles and salaries, is required by Congress each year by July 1. Two comparable reports from Obama’s White House showed 13 percent of 24 top commissioned staffers left in the same period.

Former President George W. Bush had the lowest level of turnover for modern presidents in a comparable time period, with only one top aide leaving, Kumar’s research shows.

GRAPHIC: 2018 report to Congress on White House personnel: bit.ly/2NgTH8X

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GRAPHIC: 2017 report to Congress on White House personnel: bit.ly/2sazirc

More upheaval is expected. Trump has been consulting with some advisers on a replacement for current chief of staff John Kelly, who is nearing a year in the job.

Disruption at the top ripples downward, with lower-level staffers jockeying for position with new bosses, doing work left behind by departees and training new hires, said Kathryn Tenpas, a political scientist at the Brookings Institution, a Washington think tank.

Tenpas has tracked turnover in about 60 key positions since the Reagan White House and said Trump has been going through staff at a record pace.

Under Trump, known for running a free-wheeling operation, an unusually high number of resignations have occurred under pressure, she noted.

“It undermines his agenda, because it’s not running nearly as efficiently as it could be, and the morale is also questionable,” she said.

More resignations can be expected, Tenpas said, after November’s congressional elections, when White House staff often leave for less manic-paced, private-sector jobs or to work on the next presidential election campaign.

The report is a snapshot, and does not show turnover between annual reports. Nor does it show changes in the vice president’s office and some other White House departments.

GRAPHIC: White House Transition Project - report on turnover: bit.ly/2yYp4SD

GRAPHIC: Brookings tracker of turnover in the Trump White House: brook.gs/2HX2fys

It showed high turnover in all salary levels and job types. At the second-highest level of commissioned White House staff -- deputy assistants to the president -- 43 percent of staffers named in the first Trump payroll report had left by this year’s update, versus 15 percent in the equivalent time frame for the Obama White House.

In the third-highest level - special assistants to the president - 39 percent left versus 24 percent for Obama.

The report reveals changes in titles. One of note: Ivanka Trump, who takes no salary for her work as an adviser to the president, has dropped the “First Daughter” that was part of her official title in last year’s report.