Thousands more people died after Hurricane Maria ravaged Puerto Rico in September than the island’s government has acknowledged, according to a Harvard study published Tuesday in the New England Journal of Medicine.

The official estimate issued by the Puerto Rican government was that 64 people died in the storm. But by comparing the overall death rate on the island to the same period the year before, the Harvard study found that 4,645 more people died between Sept. 20 and Dec. 31, 2017, than in that same period in 2016.

That represents a 62 percent increase in the island’s mortality rate over that year, which the study attributed to Maria.

Source: NBC News