Almost one year ago — on September 10, 2017 Hurricane Maria devastated the island of Puerto Rico.

But, it was only a few weeks ago that the Puerto Rican government finally revised its estimate for the disaster’s death toll: They now say that the storm and its effects killed around 2,975 people, up from previous estimates of only 64.

The revised numbers come from a study done by the Milken Institute of Public Health at George Washington University. The research team used a combination of data and interviews to come to understand how many people were actually killed by Hurricane Maria and in its aftermath.