WASHINGTON - The Bush administration is focusing on a Social Security (news - web sites) proposal that would allow younger workers to invest up to 4 percent of their payroll taxes in private accounts, with contributions limited to about $1,000 to $1,300 a year, an official said Tuesday. AP Photo A final plan is expected to be unveiled in late February. The official, who spoke on condition of anonymity, said the size of the private accounts could be similar to a proposal by Sen. Lindsey Graham (news, bio, voting record), R-S.C., and a plan from President Bush (news -...