Unemployment among Americans workers unexpectedly declined by 20,000 last week, the Labor Department reported Thursday. Some 278,000 laid-off workers applied for jobless benefits, which was 20,000 fewer than the previous week, and the biggest decline in five weeks, the department said. The current range of U.S. unemployment, around 4.7 percent overall, reflects a healthy jobs market. The unemployment rate fell to a 4 1/2-year low in January as businesses added 193,000 new jobs. The ever-improving jobs situation seems set to hit its best levels since before recession struck the U.S. economy in 2000. However, the Federal Reserve has been following the jobs market with a cautionary view to keeping inflation in check. Wall Street's performance in recent months has hinged on the rate balance between federally-set interest rates, jobs, and economic growth.