The fall in yields came as traders picked up bonds post economic data that showed the sort of weak trends and fall in inflationary pressures that the Fed wants to see. Before the opening bell, ADP's latest jobs report showed that private sector employment in January rose at a lesser-than-anticipated rate. Then, the employment cost index for Q4 came in, increasing at a lower-than-expected clip. Finally, Chicago PMI unexpectedly edged down in January.