The air war in Afghanistan showed the continuation of a trend in the way the USAF deals with ground targets. In the Afghanistan war, 56 percent of the bombs dropped were smart bombs. In the 1999 Kosovo war, 35 percent were smart bombs, and in the 1991 Gulf War, only five percent were smart bombs. However, the Gulf War saw 9,300 smart bombs dropped, while only 6,700 were used in Afghanistan. In 1991, there were larger stocks of smart bombs, because it was the tail end of the Cold War. Moreover, the smart bombs in 1991 cost some 50 percent more than the more effective ones used today. The latest, and most effective, smart bomb is the GPS guided JDAM. The Afghanistan operations used up 4,600 of the 10,000 available. This means that there were not enough to deal with a major operation in, say, Iraq or Korea. More are being quickly built, and stocks should be replenished by April. Fortunately, the JDAM is fairly simple technology. It's also interesting to note that of the 15,600 sorties flown, the air force, with no nearby bases, flew 45 percent of them. Of the 8,500 tons of bombs dropped, the air force accounted 75 percent of this. Most of this was dropped by 16 (10 B-52Hs and six B-1Bs) heavy bombers operating out of the Indian Ocean island of Diego Garcia. Some 72 percent of the bombs dropped by the air force were smart bombs. Air force tankers flew 3,500 sorties, refueling air force and navy aircraft.