LAGOS, May 25 (AFP) - The Nigerian naira firmed on Tuesday, rising for the second day running in open trading on the inter-bank market in Lagos, to close at 99.50 to the dollar from 100 on Monday, brokers said. The naira last week hit a low point of 106.60 naira to the dollar on speculation of an imminent devaluation. Tuesday it fell back to 158 from 156 against the pound sterling, stood unchanged steady at 55 to the German mark and firmed to 162 from 166 against 1,000 CFA francs. Dealers said that the rise against the dollar came amid growing belief that the Central Bank of Nigeria (CBN) would leave the official rate of 94.88 naira to the dollar unchanged Wednesday. The CBN, which sets the official rate at the weekly Autonomous Foreign Exchange Market, last devalued the naira on May 5. Dealers said that with just days to go before Nigeria ends military rule, swearing in a new civilian government Saturday, a new devaluation was now believed unlikely. The minimum discount rate remained unchanged at 20 percent.  