Gas stations in Japan passed an average 91.1 percent of crude oil price hikes onto petroleum products in April, up from 44.3 percent in March, a government survey showed Tuesday.

But they are still shouldering financial burdens with the margin of price increases almost doubled from the previous month, it said.

A total of 95 gas stations that responded to a monthly survey by the Natural Resources and Energy Agency raised the ratio of passing higher crude oil prices onto the products.

But their gross profit shrank by 0.44 yen per liter from March, due to an average 4.95 yen per liter price rise in April.