CEMENT sales in Bihar, West Bengal and Jharkhand rode an extraordinary construction boom to grow at a record 41%, 24% and 29% between April and December from a year ago, eclipsing the national average of 10% by a stretch. In contrast, cement demand was low in the south and stable in the west, showed data compiled by the Cement Manufacturers of India, an umbrella body of nearly 50 companies. Still, the sharp jump in consumption due to swathes of construction projects in Bihar and West Bengal, notably Kolkata, Jharkhand and Madhya Pradesh at 4.2 mt, 4.2 mt, 1.9 mt and 5.8 mt more than made up for the tepid demand in other regions, said cement manufacturers. An economic survey by the Bihar government showed that the construction sector grew 43% in 2008-09, accounting for 13% of the state