(New York Times) — Another 2.6 million people slipped into poverty in the United States last year, the Census Bureau reported Tuesday, and the number of Americans living below the official poverty line, 46.2 million people, was the highest number in the 52 years the bureau has been publishing figures on it. And in new signs of distress among the middle class, median household incomes fell last year to levels last seen in 1997. Economists pointed to a telling statistic: It was the first time since the Great Depression that median household income, adjusted for inflation, had not risen over such a long period, said Lawrence Katz, an economics professor at Harvard. “This is truly a lost decade,” Mr. Katz said. “We think of America as a place where every generation is doing better, but we’re looking at a period when the median family is in worse shape than it was in the late 1990s.” The bureau’s findings were worse than many economists expected, and brought into sharp relief the toll the past decade — including the painful declines of the financial crisis and recession —had taken on Americans at the middle and lower parts of the income ladder. It is also fresh evidence that the disappointing economic recovery has done nothing for the country’s poorest citizens.