Query: What was most of Nigeria's federal income being spent on?
Context: He set 1990 as the official deadline for a return to democratic governance. Babangida's tenure was marked by a flurry of political activity: he instituted the International Monetary Fund's Structural Adjustment Program (SAP) to aid in the repayment of the country's crushing international debt, which most federal revenue was dedicated to servicing. He enrolled Nigeria in the Organisation of the Islamic Conference, which aggravated religious tensions in the country.