NIAMEY (Reuters) - Niger's economy grew by 4.1 percent last year, beating an earlier estimate of 3.6 percent, following new data from the mining and agricultural sectors, a government statistics body said on Tuesday. Still, the pace of growth in the West African oil and uranium producer was much slower than initial forecasts given by both the International Monetary Fund (6.3 percent) and the Niger government (7.5 percent). "The GDP stands at 4.1 percent in 2013 versus the 3.6 figure estimated in November 2013 and the 11.1 percent growth in 2012," the National Institute of Statistics (INS) said in a statement. INS said that the slower economic growth last year was due mostly to a drop in agricultural output following a sharp rise in 2012.