ABUJA — Nigeria's external reserves reached $55.25 billion on 18 September, the highest in 18 years and enough to cover 11.3 months of imports, Central Bank Governor Olayemi Cardoso said after the Monetary Policy Committee meeting. The current account surplus rose to $7.54 billion in the second quarter from $4.49 billion. Cardoso said the old system of multiple foreign exchange windows had cost the country about 3 per cent of GDP, and fuel subsidies about 2.2 per cent. He described the rate cut as a recalibration rather than an easing of policy.