The U.S. military has helped tankers transport more than 660 million barrels of crude oil through the Strait of Hormuz since early May, Central Command told CNBC this week.
The military has assisted about 1,300 commercial vessels sail through Hormuz over the same period, said U.S. Navy Captain Tim Hawkins, a Central Command spokesperson, in a statement Thursday.
"Multiple routes remain free and open for commercial transit," Hawkins said.
This suggests at least 160 million barrels, or more than 7 million barrels per day, have transited the strait over the past three weeks, based on the military's past statements. Central Command said on July 29 that U.S. forces had assisted 500 million barrels through Hormuz since May.
The shipments are still far below the fuel exports before the war, when about 20 million bpd of crude oil and products passed through Hormuz. But the U.S. military's figures indicate that a substantial amount of oil is passing through the strait despite Iranian threats and attacks.
Exactly how much oil is coming out of Hormuz daily is unclear as the U.S. government has provided different estimates that are usually higher than data from independent ship tracking firms.
U.S. officials told Axios Wednesday about 10 million bpd have exited the strait in recent weeks. Energy Secretary Chris Wright said Aug. 11 that the seven-day average had risen to nearly 9 million bpd.
The maritime intelligence firm Windward estimates that crude oil exports through Hormuz averaged about 5 million bpd in July, compared to about 4 million bpd in June and 1.6 million bpd in May.
Exports in August are expected to increase over July as well, said Michelle Wiese Bockmann, senior maritime intelligence analyst at Windward.
"My assessment is that it's scaling and it's scaling quickly despite the fact that Iran is placing enormous pressure on maritime security," Bockmann said.
"The Gulf states have got U.S military protection – that's not a secret," the analyst said. They are "ready to do whatever they can" to increase their oil exports through the strait, she said.
There's a lack of solid information on exactly how much oil is moving through Hormuz due to the complexity of tracking ships during wartime, said Bridget Diakun, maritime intelligence and research director at Lloyd's List.
Ships often transit at night but satellite imagery is usually taken in the morning, Diakun said. "There's a lot of unknowns," she said at a Thursday briefing.
The U.S. energy secretary said last week that "many private businesses undercount the number of ships leaving the Strait of Hormuz due to ships moving covertly through the waterway."
"In coordination with the U.S. military, the U.S. Department of Energy maintains the best available data related to oil and oil products leaving the Arabian gulf," Wright said in a social media post.