Nigeria’s Auditor General has denounced that Nigerian National Petroleum Corporation (NNPC) withheld $16b in revenues from the federal government in 2014, the same year that the then Central Bank Governor was suspended after making similar claims, Reuters reported.

Constitutionally,  NNPC must hand over its oil revenue – which makes up about 70% of nation’s total income – and money is then paid back based on a budget approved by the parliament. According to the latest figures on OPEC’s website, Nigeria’s oil exports are worth about $77b a year.

Auditor General, Samuel Ukura, presented his findings in a report to lawmakers at the National Assembly where he said other government ministries and agencies had also failed to remit funds.

He further stated that the findings were based on an “examination of NNPC mandates to Central Bank of Nigeria (CBN) on Domestic Crude Oil Sales and Reconciliation Statement of Technical Sub-Committee of Federation Account Allocation Committee’s (FAAC) meeting held in January 2014,” RigZone reported.

In 2014, the then Central Bank Governor, Lamido Sanusi, was suspended after accusing the NNPC of failing to pay $20b into government accounts between January 2012 and July 2013.

As President Muhammadu Buhari won office last May, he promised to end the graft and mismanagement that has stunted the continent’s biggest economy. Nigeria is going through its worst economic crisis for years due to tumbling crude prices and Buhari has said that mind-boggling amounts of oil money were stolen.