Three months after Hurricane Maria ravaged Puerto Rico, only 55 percent of the island's nearly 1.5 million customers have power, according to government officials.
One of Puerto Rico's 78 municipalities remains entirely without power, and it's unclear when some electricity will be restored to the central mountain town of Ciales. Crews this week restored power for the first time to parts of the southeast coastal town of Yabucoa, which received the first hit from Maria.
Gov. Ricardo Rosselló had pledged 95 percent power generation by Dec. 15, while the U.S. Army Corps of Engineers has said the entire island will have power by May.
Fredyson Martinez, vice president of a union that represents workers with Puerto Rico's power company, told the Associated Press on Friday that a recent study by local engineers found that 90 percent of industries and 75 percent of businesses already have power, meaning residential areas are disproportionately in the dark.
PHOTOS: Hurricane Maria pummels the Caribbean
In recent days, mainland power companies have dispatched crews from Texas, Kentucky and other states to the island to assist with recovery efforts.
The Category 4 storm hit on Sept. 20 with 154 mph winds. Puerto Rico's Department of Public Safety has attributed 64 deaths to the hurricane, a figure that is under review after scrutiny from the New York Times and others.
ABC News and the Associated Press contributed to this report.
Nearly half of Puerto Rico still without power months after Hurricane Maria
U.S. & WORLD