Here's the number of top officials in Trump Administration who resigned or were fired over the last two years, with Dan Coats’s resignation being the latest one.

US President Donald Trump’s tenure continues to be a revolving door with a record-setting level of resignations and firings involving top administrative officials showing no signs of abating.
The latest high-profile resignation came in the form of Dan Coats, the Director of National Intelligence, whose official tenure was coming to an end next month.
The directorate of the National Intelligence was formed in 2004 as an umbrella organisation to lead all US intelligence agencies and track security threats in a collaborative manner.
Coats will join other high-ranking officials who have departed during Trump’s tenure, including the secretary of state, Pentagon chief and attorney general. The total number of departed officials has passed 50 since the beginning of the Trump presidency in January 2017.
Loyalism versus meritocracy
Trump signalled that he will nominate John Ratcliffe, a Texas Republican and loyalist, whose performance against the former Special Counsel Robert Mueller was praised by Trump's allies.
Mueller investigated Russia's role in influencing the 2016 US elections, which resulted in Trump being elected, and also testified before the US Congress.
The latest departure has also indicated Trump’s tendency to choose loyalists over meritorious candidates. The president has also shown dislike for those who do not toe his line on local and foriegn issues. Coats, 76, a veteran Republican, liked to express his own opinion, at times differing from Trump's views on crucial issues such as Washington's Russia policy and Iran’s nuclear capabilities.
Earlier this year Coats told a Senate committee that the intelligence community had not been convinced that Iran was developing a nuclear weapon. Trump immediately responded to him on Twitter, describing Coat’s stance as “passive and naive”. Coats, a former diplomat, has served in Congress for more than three decades.
Here we sum up other high-level exits during the Trump presidency:
Sarah Huckabee Sanders
Last month, White House Press Secretary Sarah Huckabee Sanders, a loyalist, also stepped down from her post despite apparently having no issue with the president himself.
She has been replaced by Stephanie Grisham, one of the First Lady’s top advisers.

Jim Mattis
US Defense Secretary Jim Mattis, arguably the most respected foreign policy official, resigned on December 20 after Trump announced an abrupt withdrawal of US troops from Syria.
“You have the right to have a secretary of defence whose views are better aligned,” the defence secretary told Trump in his resignation letter after two years of deep disagreements with Trump over America's role in the world.
Ryan Zinke
Trump announced on December 15 that Zinke would be leaving the administration at the end of the year after having served for a period of almost two years as the US Secretary of the Interior.
Zinke is one of several members of Trump's cabinet to come under fire over expenditures, including reports that his department was spending nearly $139,000 to upgrade three sets of double doors in his office - a cost he later said he negotiated down to $75,000.

Nick Ayers
Ayers announced that he would leave the White House at the end of 2018 where he served as the chief of staff to Vice President Mike Pence. His resignation came as he declined Trump's offer to be his new chief of staff to replace John F. Kelly.

John F. Kelly
A retired US Marine Corps general, Kelly was selected as the first Secretary of Homeland Security in the Trump administration on January 20, 2017. Then, he had served as chief of staff in Trump’s White House from July 2017 to January 2019. He was also forced to resign from his post by Trump.
Jeff Sessions
Became attorney general of the United States on February 8, 2017. After a turbulent tenure and tense relations with Trump over Special Counsel Mueller’s Russian probe, he was forced to resign by Trump on November 7, 2018.

Nikki Haley
Served as the United States ambassador to the United Nations since January 25, 2017. She resigned on October 9, 2018 and left her post at the end of 2018.
Scott Pruitt
Sworn in as Environmental Protection Agency administrator on February 17, 2017. He stepped down on July 5, 2018.

Herbert Raymond McMaster
Assumed post of national security adviser of the US on February 20, 2017. He was fired by President Trump on March 22, 2018.
Gary Cohn
Served as chief economic adviser to the US president from January 20, 2017 until he resigned from the post on March 6, 2018.

Hope Hicks
Became White House Communications director on the same day Trump assumed office on January 20, 2017. She resigned on February 28, 2018.
David Shulkin
Served as Veterans Affairs secretary from January 20, 2017 till the day he was fired on March 28, 2018.

Rex W Tillerson
Became the US Secretary of State on February 1, 2017. He was fired on March 13, 2018.
Omarosa Manigault Newman
Became assistant to the president and director of Communications for the Office of Public Liaison on January 20, 2017. She resigned on December 13, 2017.

Tom Price
Served as United States Secretary of Health and Human Services since February 10, 2017. He resigned on September 29, 2017.

Sebastian Gorka
Became White House deputy assistant on January 24, 2017. He resigned on August 25, 2017.

Steve Bannon
Bannon, a controversial figure having ties with supremacist groups, became White House Chief Strategist on January 20, 2017. He was fired on August 18, 2017.

Anthony Scaramucci
Served as White House Communications Director for 10 days between July 21, 2017 and July 31, 2017. He was fired.

Reince Priebus
Became White House Chief of Staff on January 20, 2017. He was fired on July 28, 2017.

Sean Spicer
Served as White House Press Secretary from January 20, 2017 till the day he resigned on July 21, 2017.

James Comey
Only Obama-era appointee on this list who served as Director of the Federal Bureau of Investigation (FBI) since 2013. He was fired by Trump on May 9, 2017.
Michael Flynn
Served as United States National Security advisor from January 20, 2017 till February 13, 2017. He was also fired.