"Percentage Used: Contains a vendor specific estimate of the percentage of life used for the Endurance Group based on the actual usage and the manufacturer’s prediction of NVM life. A value of 100 indicates that the estimated endurance of the NVM in the Endurance Group has been consumed, but may not indicate an NVM failure. The value is allowed to exceed 100."
for SATA/SAS SSDs, there is "Media_Wearout_Indicator" which hasn't been a particularly reliable indicator in my experience.