NEW YORK (Reuters) - People across the eastern United States enjoyed cooler, drier air on Thursday after a suffocating heat wave ended and electricity was mostly restored after several sweltering days that killed at least 71 people. The highest number of deaths was reported in Philadelphia, where 40 mostly elderly people who lived in the city‘s ageing brick row houses fell victim to record heat and humidity that set in over the weekend. "The brick (in the row houses) really retains the heat and when it‘s so hot like this for several days these structures just boil," Philadelphia Health Department spokesman Jeff Moran said. Moran said many people used fans to try to keep cool, which did not help. "People don‘t realise that using a fan in a hot, unventilated room creates a kind of oven." Officials said those who died may have not had air conditioners on because they worried about payment of the electricity bills or kept their windows closed for fear of crime. Dr. Lawrence Robinson, the city‘s deputy health commissioner, noted that the majority of the deaths were elderly people, many with chronic illnesses. The New York City Medical Examiner‘s office said 19 deaths from the heat had been confirmed as of Thursday. Most of the deaths were caused by hyperthermia, when body temperature exceeds 40.5 degrees Celsius. Mayor Rudolph Giuliani said the toll could be as high as 25. Five people were reported to have died in New Jersey, two in the Pittsburgh area, three in New England and two in Washington. But the region breathed easier in cooler, drier air on Thursday. After the sweltering weather started on Saturday, temperatures in some of those cities rose to 100 degrees Fahrenheit (38 degrees Celsius) or higher, coupled with stifling humidity. The heat wave buckled roads and bridges, hit power supplies and sent people suffering from heat exhaustion to hospital emergency rooms throughout the region.