There was at least one acting secretary (out of the 15 core posts) for 83% of President Trump's four-year term.
— Brian Kalt (@ProfBrianKalt) March 22, 2021
The Cabinet was full for 3 stretches totaling 252 days:
2017: 4/28 to 7/31 (94)
2018: 1/29 to 3/28 (58) and 7/30 to 11/7 (100)
2/2