The classic case of a corrupt, exploitive dictator often given is the regime of Marshal Mobutu Sese Seko, who ruled the Democratic Republic of the Congo (which he renamed Zaire) from 1965 to 1997. It is said that usage of the term kleptocracy gained popularity largely in response to a need to accurately describe Mobutu's regime. Another classic case is Nigeria, especially under the rule of General Sani Abacha who was de facto president of Nigeria from 1993 until his death in 1998. He is reputed to have stolen some US$3–4 billion. He and his relatives are often mentioned in Nigerian 419 letter scams claiming to offer vast fortunes for "help" in laundering his stolen "fortunes", which in reality turn out not to exist. More than $400 billion was stolen from the treasury by Nigeria's leaders between 1960 and 1999.