Recovery from the worst recession since the 1930s has begun as President Barack Obama’s fiscal stimulus — derided as insufficient and budget-busting a few months ago — takes effect, a survey of economists indicated.

The economy will expand at an annual rate of 2 percent or more in four straight quarters through June 2010, the first such streak in more than four years, according to the median of 53 forecasts in a monthly Bloomberg News survey. Analysts lifted their estimate for the third quarter by 1.2 percentage points compared with July, the biggest such increase in surveys dating from May 2003.

“We’ve averted the worst, and there are clear signs the stimulus is working,” said Kenneth Goldstein, an economist at The Conference Board in New York.

The Bloomberg Professional Global Confidence Index jumped to 58.12 this month from 39.13 in July. A measure of U.S. participants’ confidence in the American economy rose to 47.3 from 29.5, the survey showed.

The anticipated expansion in the coming year won’t be enough to prevent the unemployment rate from reaching 10 percent for the first time since 1983, the survey also showed. That will force the Federal Reserve to forgo raising its benchmark interest rate until the third quarter of 2010, according to the median projection.

The Fed’s policy-setting Federal Open Market Committee (FOMC) will today keep the target federal funds rate at zero to 0.25 percent and retain plans to buy as much as $1.45 trillion of housing debt by year’s end to help secure a recovery, analysts said. The FOMC’s statement is expected at about 1:15 p.m. Central Time in Washington.

The Fed is expected to end its program of buying long-term government securities at the meeting, which concludes today, but keep U.S. interest rates steady at near zero amid signs the economy is stabilizing from a deep recession.