A new study led by 91自拍ers at the 91自拍 and the University of California, Davis, finds that the success rate of summiting Mount Everest has doubled in the last three decades, even though the number of climbers has greatly increased, crowding the narrow route through the dangerous 鈥渄eath zone鈥 near the summit. However, the death rate for climbers has hovered unchanged at around 1% since 1990.







































