Puerto Rico has raised the toll from last year’s Hurricane Maria from 64 to nearly 3,000 after a study ordered by the government of the American territory. The study found that 2,975 deaths could be attributed directly or indirectly to the hurricane between September 2017 and February 2018, Reuters reported.

The government had made the estimate of 64 deaths in December 2017, three months after the hurricane. The new toll is also an approximation, and not a concrete list of names, Governor Ricardo Rossello said on Tuesday, according to CNN.

Officials will continue to investigate deaths and revise the official tally, Rossello said. Calling it “unprecedented devastation”, the governor said coming up with a full list of deaths may take months or years.

“This number can change,” he said. “It could be less, it could be more, as time passes. We are using the best science available...to be able to give a sense of closure to all of this. The truth is there is a lot of work to do.”

The government-commissioned study was conducted by researchers from George Washington University.

Hurricane Maria was the most powerful storm to hit the Caribbean island in nearly 90 years. Coming soon after Hurricanes Harvey and Irma, it was third major hurricane to hit the region within a month. More than 80% of the island’s population were left without electricity and a third lost access to reliable drinking water at home for weeks.