The U.N. says civilian deaths in Afghanistan rose 40 percent in 2008 to a record 2,118.An annual U.N. report says militants were responsible for 55 percent of civilian deaths last year, or 1,160. But the world body says U.S., NATO or Afghan troops killed 829 - 39 percent of the total.The remaining 130 deaths couldn't be accounted for because of issues like cross-fire.Civilian deaths have been a huge source of friction between the U.S.