The Nigerian government has removed nearly 24,000 employees from its payroll after an audit ordered by President Muhammadu Buhari revealed the civil servants did not exist, the country’s finance ministry said Sunday. The move has allowed the federal government to save about $11.5 million from its monthly wage bill, according to Reuters.

The audit began in December using biometric data and a bank verification number, or BVN, to identify the account holders into which government salaries were being deposited. This revealed that the names of some workers receiving salaries did not match up to the names linked to the bank accounts. In some instances, individuals were getting paid from multiple sources.

"The federal government has removed 23,846 non-existent workers from its payroll," Festus Akanbi, special adviser to Nigerian Finance Minister Kemi Adeosun, told Reuters Sunday. "Consequently the salary bill for February 2016 has reduced by 2.293 billion naira when compared to December 2015 when the BVN audit process commenced.”

Akanbi said the finance ministry had so far checked the details of some 312,000 government workers. Going forward, the finance would assume “periodic checks and utilize computer-assisted audit techniques” and also introduce stricter monitoring of new entrants to the civil service to prevent further abuse of the payroll system. Personnel costs currently take up more than 40 percent of Nigeria’s total government expenditure

The finance minister, Adeosun, took office in November and set up an efficiency unit soon after to cut costs as part of Buhari’s efforts to crack down on corruption and mismanagement, which have long hindered development in Africa’s largest economy and top oil producer. Nigeria is ranked 136 out of 167 countries on the Transparency International Corruption Perceptions Index 2015, making it one of the worst performers in Africa. A steep fall in global oil prices has exacerbated Nigeria’s financial crisis.

"The ongoing exercise, which is part of the cost-saving and anti-corruption agenda of President Muhammadu Buhari's administration, is key to funding the deficit in the 2016 budget," Akanbi told Reuters Sunday.

Since taking office in May, Buhari has vowed to recover federal revenue looted by corrupt officials. But a precedent of government corruption in other countries suggests it is unlikely the Nigerian leader will recoup the funds in a timely fashion. A  study published in 2014 showed that the Philippines economy lost $132.9 billion because of illicit government spending in the past five decades -- money that has never been returned and otherwise could have helped the impoverished nation’s economy grow.