Advocates for low-income Mainers are presenting a report that highlights the impact of poverty on children, families and seniors.The Maine Community Action Association released its annual Poverty Report Update on Thursday. The report was prepared by the Margaret Chase Smith Center at the University of Maine.The report highlights newly released county-by-county poverty data from the 2010 U.S. Census.The report finds significant low-income populations in rural as well as urban counties. The three counties with the highest poverty rates were Washington at 19.4 percent, Somerset 18.6 percent and Piscataquis 16.6 percent. The report says Maine’s child poverty rate is 18.2 percent. In 11 of Maine’s 16 counties, more than one in five children lives in poverty.The federal poverty level for a family of four is $22,000.