A review of crash data compiled by U.S. officials indicated 303 people died after the air bags failed to deploy in two passenger car models recalled last month. The Friedman Research Corp. review of the air bag failures from 2003 to 2012 adds to the growing reports of problems that went unaddressed before General Motors Co. announced last month it was recalling more than 1.6 million cars worldwide because of a defective ignition switch, the New York Times reported Thursday. The automaker linked 12 deaths and 31 crashes to the faulty switch in the two models analyzed by Friedman -- the 2005-2007 model year Chevrolet Cobalt and 2003-2007 Saturn Ion -- and four other models. The review by Friedman, a company that analyzes vehicle safety data, examines cases in which air bags failed to deploy, but said it didn't try to evaluate the crashes' causes, the Times said. The study was commissioned by the Center for Auto Safety, a private watchdog group in Washington. In a letter to the National Highway Traffic Safety Administration, the center criticized the agency for not detecting air bag failures or the defective ignition switch. "NHTSA claims it did not do an investigation because it did not see a defect trend," center Executive Director Clarence Ditlow wrote in the letter. "In some instances, single complaints can trigger a recall." Regulators said that there was still not enough evidence to warrant an investigation. "In this case, the data available to NHTSA at the time did not contain sufficient evidence of a possible safety defect trend that would warrant the agency opening a formal investigation," the agency said. GM has criticized the use of the Fatality Analysis Reporting System database used in the study, the Times said. "As knowledgeable observers know, FARS tracks raw data," GM spokesman Greg Martin said. "Without rigorous analysis, it is pure speculation to attempt to draw any meaningful conclusions."