Infrastructure growth declined marginally to 4.7% in December 2005 from 4.8% a year ago, largely on account of a sharp decline in crude oil output and poor performance in the power sector.The core sector growth would have been much lower but for the robust performance in the cement industry and a rebound in steel production. While cement production rose 13.4% in December 2005 when compared with 8.3% in the same month a year ago, steel production increased by 6.7% as against 3.8% in December 2004.Crude oil production fell sharply to register a negative growth of 8.1% in December 2005 as against a negative growth of 0.6% in December 2004. Electricity sector posted a growth of only 2.9% as against 4.4% in the year-ago month, according to data released by the government today.While coal production grew at a slower rate of 6.6% when compared with 7.7% in December 2004, refining throughput increased 8.8% as against 9.2%.Cumulative growth of the six sectors between April-December 2005-06 declined to 4.5% when compared with 6.4% in the corresponding period a year ago.