On Friday, June 17, 2016, the Central Bank of Nigeria (CBN) abandoned the Nigerian naira's (NGN) fixed exchange rate and allowed the currency to float. Previously fixed against the U.S. dollar at NGN 194.87 = 1.00 USD, the naira closed at NGN 277.52/USD on Monday, June 20, the first day of trading following the float. The naira quickly floated (sunk) to NGN 322.51/USD by August 18. Similarly, the naira fell from NGN 218.5062 = 1.00 EUR to NGN 314.5169/EUR on June 20, and NGN 346.1898/EUR on August 18.

c. What was the percentage change in the value of the Nigerian naira versus the euro on the first trading day?