Answer based on context:

Pilgrims circumambulate the monastery on the lingkhor  outside the walls. Fortunately, although two-thirds of the buildings were destroyed during the excesses of the Chinese Cultural Revolution, they were mainly the residences for the 4,000 monks and the monastery itself was not as extensively damaged as most other religious structures in Tibet, for it was the seat of the Panchen Lama who remained in Chinese-controlled territory. However, during 1966 Red Guards led a crowd to break statues, burn scriptures and open the stupas containing the relics of the 5th to 9th Panchen Lamas, and throw them in the river. Some remains, though, were saved by locals, and in 1985, Choekyi Gyaltsen, 10th Panchen Lama, began the construction of a new stupa to house them and honour his predecessors. It was finally consecrated on 22 January 1989, just six days before he died aged fifty-one at Tashi Lhunpo. "It was as if he was saying now he could rest."

How many percent of buildings were not destroyed during the Chinese Cultural Revolution?
33.3