Oil industry cautions government against boosting fuel oil reserve July 19, 2000 Web posted at: 8:55 p.m. EDT (0055 GMT) WASHINGTON (CNN) -- Summer gasoline prices may have reached their peak. The American Automobile Association reported Wednesday that the national average price for regular unleaded fuel dropped to $1.57 a gallon, down from $1.64 a month ago. Rates have plummeted in the Midwest where consumers were paying record high prices. In Chicago, the average price dropped from $2.13 last month to $1.64 today.   ALSO U.S. thirsty as ever for imported oil   The American Petroleum Institute once again blamed new clean-fuel regulations for the June hikes in it's midyear report on crude oil prices released Wednesday. API President Red Cavaney denied allegations that price drops were tied to an impending investigation into price gauging by the Federal Trade Commission. He said the decline began before the FTC announcement. "The FTC was a Johnny-come-lately and really had nothing to do with starting the downward momentum," Cavaney said. He added that the industry is less able to deal with a regional fuel shortages because of a shortage of refineries.