WASHINGTON (AP) -- U.S. job growth slumped in April for a second straight month. It pointed to a steadily growing but still sluggish economy that could tighten the presidential race.

A drop in the unemployment rate wasn't a necessarily a healthy sign for the job market. The rate fell from 8.2 percent in March to 8.1 percent in April. But that was mainly because more people gave up looking for work.

People who aren't looking for jobs aren't counted as unemployed.

The 115,000 jobs added in April were fewer than the 154,000 jobs created in March, a number the government revised up from its first report a month ago of 120,000. It also marked a sharp decline from December through February, when the economy averaged 252,000 jobs per month.

The percentage of adults working or looking for work has fallen to its lowest level in more than 30 years. Many have become discouraged about their prospects.

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Here's what The Associated Press' reporters are finding:

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TEPID ECONOMY, TEPID HIRING

Over time, strong economic growth is vital for strong job growth.

But early this year, hiring accelerated much faster than economic growth did. Job gains averaged a strong 229,000 in the first three months. But the economy grew at a sluggish annual rate of 2.2 percent.

Economists began to wonder: Would growth catch up with hiring? Or would hiring slow to match economic growth (as measured by gross domestic product, or GDP)?

Some economists say April's disappointing job growth suggests an answer, and it's not a cheerful one:

"It now appears that jobs have decelerated into line with GDP, rather than GDP accelerating to catch up with jobs," said Nigel Gault, an economist at IHS Global Insight.

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REVISING HISTORY

The job market seems to look better with hindsight.

The Labor Department has revised job growth upward for 10 straight months - and for 18 of the past 21. Over the past 10 months, it's added 413,000 jobs to the original estimates.

The job figures are revised twice. They're updated in the two months after they first come out. And they're revised again in an annual update meant to capture updated employment data from the states.

History shows that the updated totals typically follow the trend in job creation: When the economy is creating jobs consistently, the revisions tend to be positive. Months of job losses typically lead to negative revisions.

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THE POLITICAL DEBATE

A falling unemployment rate would seem to be good news for President Barack Obama's re-election hopes. Dating to 1956, no incumbent president has lost when unemployment fell in the two years leading to an election.

On Election Day, unemployment will almost surely be less than it was two years earlier: 9.8 percent in November 2010.

But for the past two months, the rate has fallen for the wrong reason: More than 500,000 Americans have stopped looking for jobs and are no longer counted as unemployed. Job growth averaged a healthy 252,000 from December through February. It slowed to 135,000 in March and April.

The question is whether voters will focus more on the falling unemployment rate (good for Obama) or the modest job growth (not so good).

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A JAB FROM ROMNEY

Mitt Romney seized on the latter. He noted that the declining number of people seeking work explains the drop in the unemployment rate.

"This is way off from what should be happening in a normal recovery," Romney said on Fox & Friends. "You have more people dropping out of the work force than you have getting jobs."

"This is not progress," Romney said.

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DISAPPEARING WORKERS

The percentage of Americans 16 and older working or looking for work is now 63.6 percent, the lowest since 1981. For men, the so-called "labor force participation rate" is 70 percent. That's the lowest since the government started keeping records in 1948.

The rate peaked at 67.3 percent in early 2000 as women poured into the workplace. Since then, it's turned south. Demographic and social trends help explain the drop: Baby boomers are aging and retiring.

And more women, especially in upper-income families, are staying at home. The drop in participation accelerated after the economy slid into recession in late 2007. The tough job market led many to give up looking for work.

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   SOUR INVESTORS

The stock market didn't take Friday's news well.

The Dow Jones industrial average sank 132 points, or 1 percent, in late-morning trading. The broader Standard & Poor's 500 index fell 1.4 percent.

   Investors were a lot happier earlier this week. They sent the Dow to its highest close since December 2007.

   Technology stocks and banks led the market lower Friday. Utility companies were the only broad category of stock in the S&P 500 index trading higher. They tend to fare well when investors grow nervous about the economy.

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NO SURPRISE TO BERNANKE

One person not likely surprised by the sluggish hiring in April: Ben Bernanke.

The Federal Reserve chairman has cautioned for months that the spike in hiring at the start of the year didn't match the economy's more modest growth.

His Fed colleagues probably agree. Their latest forecasts show that even under a best-case scenario, unemployment will be at least 7.3 percent in late 2013. Historically, a normal rate would range between 5 percent and 6 percent.

Most analysts expect the Fed to keep its key interest rate at a record low near zero well into 2013, if not later. But few think hiring has weakened enough to trigger a third round of bond buying to help lower long-term rates and encourage more lending.

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A LONG WAY TO GO

The United States has regained only 43 percent of the 8.78 million jobs lost from February 2008 to January 2010.

So far this year, the economy has generated 201,000 jobs a month. At that rate, it would take until May 2014 to restore employment to its 2008 peak of 138 million.

Of course, the population has grown since then. So it could take even longer to lower the unemployment rate to its 2008 level.

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Associated Press writers Martin Crutsinger and Kasie Hunt contributed to this report.

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