Donald Trump once bragged that his Cabinet had “by far the highest IQ of any Cabinet ever assembled.”

That was said in January of last year.  Since then fully one-quarter of the geniuses are gone, the latest being VA Secretary David Shulkin.  From NPR:

The four Cabinet members Trump has already replaced are Health and Human Services Secretary Tom Price, who was pushed out after controversy over flying in charter aircraft; Homeland Security Secretary John Kelly, who became chief of staff over the summer; Secretary of State Rex Tillerson, who was fired by tweet recently over policy and personality clashes; and now Shulkin, who had been embattled in recent weeks over both policy disagreements and an inspector general’s report that found he improperly had taxpayers cover travel expenses for his wife.

 No elected president has had this much turnover in the last century.
In just 14 months on the job, Trump has had more Cabinet turnover than 16 of his predecessors had in their first two years. 
Rex Tillerson had the shortest tenure of any modern Secretary of State at just 405 days.
And the firings may not be finished.  Trump is said to be frustrated with HUD Secretary Ben Carson, he of $31,000 dining room table fame.