WASHINGTON, May 25 (Reuters) - The stimulus law enacted in 2009 to help jolt the United States out of recession continued to pay dividends this year by adding jobs and expanding the economy, the Congressional Budget Office said on Wednesday.

For the first three months of this year, the stimulus law lowered the nation’s unemployment rate by between 0.6 percentage points and 1.8 percentage points, the non-partisan budget and economic analyst for Congress estimated.

Even with that boost, the U.S. jobless rate for April was 9 percent, rising somewhat from 8.8 percent the previous month as more people entered the job market.

The CBO estimated that as a result of the stimulus spending, somewhere between 1.2 million and 3.3 million more people were employed in the first quarter.

When it was being debated, some in the Obama administration estimated the huge stimulus would prevent the U.S. unemployment rate from rising above 8 percent. Instead, the jobless rate reached a high of 10.1 percent in October, 2009, and one year later had dropped only to 9.7 percent.

The overall U.S. economy benefited, CBO said, as inflation-adjusted gross domestic product rose by between 1.1 percent and 3.1 percent because of the measure.

Republicans, who voted against the economic stimulus law when it was moving through Congress, have insisted that the measure created few if any jobs and has exploded U.S. budget deficits that are estimated to be around $1.4 trillion this year.

CBO estimates the stimulus law will increase budget deficits by about $830 billion over 10 years.

The economic stimulus bill was aimed at injecting federal funds for construction and research projects throughout the United States. (Reporting by Richard Cowan)