Insurance company UnitedHealth Group is confirming a ransomware attack earlier this year affected the private data of over 100 million people. The number was published in the US Department of Health and Human Services Office of Civil Rights (OCR) Breach Report on Thursday, making it the largest healthcare data breach on the list.

The scope of the attack makes it the largest healthcare data breach ever, surpassing an Anthem incident in 2015 that affected almost 79 million Americans. According to a testimony

Data recently posted on a federal website shows the cyberattack earlier this year at a UnitedHealth Group subsidiary affected 100 million patients — apparently a U.S. record. The tally roughly matches the scope previously described by company Chief Executive Andrew Witty,