President Donald Trump has lost 41% of the Cabinet secretaries, deputy secretaries and under secretaries he appointed in his first year in office, new data from the Partnership for Public Service‘s Center for Presidential Transition shows.

Why it matters: This far outpaces the turnover rate for recent predecessors at the same stage of their presidencies — and underscores the challenges Trump may face in recruiting and retaining a new stable of top officials if he wins re-election.

Details: The center, which is launching its 2020 program Thursday, looked at historical turnover data for high-level positions requiring Senate confirmation from Presidents Bill Clinton, George W. Bush and Barack Obama, each of whom was elected to a second term.

Each had lower turnover levels than Trump at this point in their tenure, measured across 15 Cabinet-level departments.

Each also saw a spike in resignations in Year 5, typical as first-term officials reach levels of exhaustion and incumbents seek fresh eyes and energy, the center's new director David Marchick told Axios.

On average, 43% of top officials serving near the end of the first term left within the first six months after the incumbent presidents’ re-elections.

But Trump’s turnover is already nearly that high, less than 3 years in.

Between the lines: How a president fills the roughly 4,000 politically appointed positions, more than 1,200 of which require Senate confirmation, is crucial to the administration's success. The 2020 Democratic challenger could face filling all of those appointments. And Trump could see another wave of departures if he’s re-elected, similar to past presidents.

"Unless you do all the prep work, you are going to wind up slow to start," Max Stier, president and CEO of the organization, told Axios. "You can't be an effective president if you're not ready."

The center has provided support to presidential hopefuls and incumbents as they prepare for a new or second-term administration.

Their 2020 kickoff event Thursday afternoon will feature a discussion with former Bush and Obama chiefs of staff Joshua Bolten and Denis McDonough.

Go deeper: Every high-profile Trump administration departure