President Donald Trump is a little more than three months into the third year of his presidency, and already, turnover in his cabinet is outpacing his recent predecessors’ entire first terms.

Trump announced that Secretary of Homeland Security Kirstjen Nielsen would be the latest to leave and will be replaced with Customs and Border Protection chief Kevin McAleenan in an acting role.

Nielsen’s was the second exit from the cabinet in 2019, coming on the heels of 10 departures in 2018 and three the year before that, according to this Brookings Institution tracker. Those who have come and gone include former Secretary of State Rex Tillerson and ex-Attorney General Jeff Sessions. The Brookings tally also includes those — like Mike Pompeo — who have left one cabinet position (heading the Central Intelligence Agency) to go to another (leading the State Department).

Adding all that up, departures from cabinet positions in the Trump era to date are up to 15.

By comparison, according to the same Brookings study, there were 12 departures in President Bill Clinton’s entire first term.

Among Trump’s last three predecessors, it’s Clinton whose first term was busiest with cabinet comings and goings. More officials stuck around in the George W. Bush administration, which had just four departures in the first four years. The tally for Barack Obama’s first term was more than double Bush’s, at nine.

Trump’s first year saw three departures, two of whom — Health and Human Services Secretary Tom Price and Chief of Staff Reince Priebus — resigned under pressure. John Kelly went from heading Homeland Security to White House chief of staff, a position he left in January.

In the past three administrations, no one left in the first year, Brookings notes.