More Americans are living in poverty than they have in 52 years, according to census data released Tuesday. About 46.2 million people, or 15.1 percent of the population, are considered in need, which the government currently defines as having an income of $22,314 a year for a family of four or $11,139 for an individual. Middle-class income also inched downward in 2010, from $49,777 to $49,445. It was also the first time since the Great Depression that the median household income, adjusted for inflation, did not rise over a long period, said Lawrence Katz, a economics professor at Harvard. Overall, Americans’ median income has stagnated: people make only 11 percent more than they did in 1980, while consumer prices have risen about 150 percent.