Story highlights Hurricane Maria's power outages are larger than Sandy and Katrina

Puerto Rico was hit by both Hurricane Irma and Maria this summer

(CNN) In terms of the total number of lost hours of electricity, Puerto Rico and the US Virgin Islands are in the midst of the largest blackout in US history, according to a report from an economic research company.

In all, Hurricane Maria has caused a loss of 1.25 billion hours of electricity supply for Americans, according to the analysis from the economic research firm Rhodium Group . That makes it the largest blackout in US history, well ahead of Hurricane Georges in 1998 and Superstorm Sandy in 2012, the group said.

That 1.25 billion number will continue to grow. More than a month after Hurricane Maria knocked out the electric grid on the islands, the vast majority of residents remain without electricity, and the restoration of that power is months away

The Rhodium Group analysis largely relies on data on electricity loss provided to the Department of Energy, as well as news reports for storms prior to 2000, according to Trevor Houser, a partner at Rhodium who co-wrote the analysis with Peter Marsters.

Houser said the group analyzes the economic impacts of weather and climate events, and they decided to dig in more deeply on the impacts of Maria on the Puerto Rican economy.

Read More