New Delhi, July 12 :     Industrial growth dropped to 5.5 per cent in May this year from 12.2 per cent in the previous month. It had posted a growth of 7.6 per cent in May 1999. The manufacturing sector, which accounts for nearly four-fifths of the total weight of the index for industrial production (IIP), registered a lower growth rate of 5.8 per cent in May this year, compared with 8.9 per cent in May 1999. According to quick estimates of the IIP released by the Central Statistical Organisation (CSO) today, cumulative growth rate during the first two months of the current fiscal was marginally low at 5.5 per cent, as against 5.6 per cent registered during April-May 1999. One of the reasons for the deceleration in industrial production could be the changes incorporated in the IIP basket and growth rates in the case of certain industry segments have accordingly undergone some changes, the CSO said. The manufacturing sector grew by 5.9 per cent as against a 7.1 per cent growth registered in the same period last year. Industrial growth slumped despite better performance in the mining sector, which grew by 2.3 per cent in May this year, compared with 0.3 per cent last year, while the electricity sector registered a higher growth rate of 5.4 per cent this year compared to 3.3 per cent in the previous comparable period. The cumulative growth in mining during the first two months of the current fiscal was 3.6 per cent, as against a negative growth rate of 0.9 per cent in April-May 1999. In the electricity sector, the cumulative growth declined to 4.5 per cent from 4.7 per cent in 1999. The consumer goods segment registered a growth rate of 10 per cent in May this year as against 2.9 per cent in the same month last year.