A hike in gas taxes has hurt the popularity of President Felipe Calderon, according to a poll published Monday.

Calderon's approval rating sank 7 percentage points, from 64 percent in August to 57 percent this month, according to the Ipsos-Bimsa poll for the Mexican newspaper El Universal.

The percentage of Mexicans who disapproved of Calderon's performance increased from 20 percent to 33 percent, the poll said.

"The increase in gas prices damaged the president's image more than any other issue," the polling company said in a news release.

In September, Mexico's Congress passed a fiscal reform bill that included a 5.5 percent hike in gas taxes. Although Calderon had proposed the increase, just days after the measure was approved he announced that it wouldn't go into effect until 2008 to avoid destabilizing the Mexican economy.

Just under 1,000 people were interviewed in person from Oct. 26-31 for the poll, which had a margin of error of plus or minus 3.5 percentage points.