CHICAGO — Taking Social Security benefits early comes with a price, yet more than 4 in 10 Americans who are 50 and over say they'll dip into the program before reaching full retirement age. An Associated Press-NORC Center for Public Affairs Research poll released Thursday found that 44 percent report Social Security will be their biggest source of income during their retirement years. Full benefits begin at 65 or 66 for those born between 1943 and 1954.