At least 460 million records were exposed in data breach incidents that were reported in May. The figure is a very conservative estimate as it reflects only publicly reported events. In many cases, the amount of data exposed to unauthorized users was not provided, so the number is likely much higher. The company counted 8.8 billion records exposed in May but 8.3 came from a single incident at AIS mobile operator in Thailand, who exposed a database of DNS query and NetFlow logs. January shows with the largest number of exposed records, 1.5 billion from 61 incidents.
Source: https://www.bleepingcomputer.com/news/security/over-460-million-records-exposed-in-breach-incidents-reported-in-may/