A key measure of the US economy gained in February, signalling a continuing moderate recovery, dpa cited a private research group as saying today. The New York-based Conference Board's index of leading economic indicators rose 0.1 per cent in February, the 11th straight monthly gain but less than the 0.3 per cent of January. The index, which gauges economic performance for the coming 3-6 months, rose 1.2 per cent in December and 1.1 per cent in November.