That's because Trump has had more control over Fed personnel than any president since the Fed was founded in 1913. As I've written before, Trump now "owns" the Fed.
When Trump was sworn in, he inherited two vacant seats on the seven-person board of governors of the Federal Reserve System. Holders of those two seats are also members of the Federal Open Market Committee (FOMC), the group that sets U.S. interest rates and monetary policies.
President Obama also had the same vacancies, but he did not nominate anyone to fill the seats because he doubted his chances of getting the nominees past the Republican-controlled Senate and he was sure "President Hillary" would do the right thing and appoint pro-Democratic nominees.
In the end, Trump beat Clinton and the vacancies fell to Trump. Then Trump got another windfall. Within 14 months of becoming president, three additional Fed governors resigned (Dan Tarullo, Stan Fischer and Janet Yellen), and Trump suddenly had five vacancies to fill, or 70% of the entire Fed board.