Core infrastructure industries grew by a robust 9.4 per cent in January against meagre 2.2 per cent in the year-ago period reflecting the sound state of recovery in industrial production. Six key sectors – crude, petroleum refinery products, coal, electricity, cement, finished steel- showed a growth of 5.4 per cent in April-January 2009-10 against 3 per cent in the same period last year, an official statement said today. These sectors have a weight of 26.68 per cent in the country's total industrial output. Finished steel and cement expanded by 16.2 per cent and 12.4 per cent, respectively in January, against 3.2 per cent and 8.3 per cent last year. Petroleum refinery products recorded expansion of 3.8 per cent against a dip of 1.3 per cent last year.