The U.S. Defense Department has estimated that it will cost nearly four-and-a-half billion dollars to station troops in South Korea in fiscal year 2020. 

According to a Pentagon budget estimate drawn up in March, the total payment toward military personnel, operations, maintenance and family housing in South Korea amounts to four-point-46 billion dollars in the fiscal year ending on September 30, 2020. 

The U.S. is reportedly asking Seoul to pay five billion dollars next year to share the costs for the upkeep of 28-thousand-500 American troops in South Korea. 

Conservative author and former presidential adviser Doug Wead says in a new book published this week that U.S. President Donald Trump may have had those figures in mind when he expressed discontent over U.S. alliance commitments. 

Trump reportedly told Wead that the U.S. spends four-point-five billion dollars a year to defend South Korea.