TRENTON — New Jersey’s unemployment rate fell significantly again in April to 8.7 percent — the lowest it’s been in four years, the state Department of Labor said Thursday.

The rate, which was 9 percent in March, declined 0.3 percentage points for two opposing reasons.

The encouraging reason is that the seasonally adjusted number of people working in nonfarm jobs grew by 3,300. The discouraging reason is that 4,400 people stopped looking for work in April.

Gov. Chris Christie’s administration described achieving the lower rate as a success.

“The marked decline in unemployment over the last year mainly reflects the ongoing gains in jobs we are experiencing,” Charles Steindel, the state Treasury Department’s chief economist, said in a statement.

He noted that 60,000 more New Jersey residents had jobs last month than in April 2012. That’s the biggest 12-month gain in seven years.

Gordon MacInnes, president of the liberal think tank New Jersey Policy Perspective, said in a statement that it’s good to see the jobless rate fall under 9 percent for the first time since May 2009, but that “it would be foolish to claim victory and to assume that the state’s economy has recovered. It hasn’t.”

He also said that the newly created jobs in New Jersey have been relatively low-wage.

New Jersey Business & Industry Association President Philip Kirschner called the state’s private-sector job growth encouraging.

The state labor department reported that 4,100 private sector jobs were added in April, for a 12-month increase of 59,600 of such jobs.

“The year-to-year gain of 59,600 private-sector jobs is very strong and the lower unemployment rate is now starting to demonstrate the strength of that job growth,” Kirschner said in a statement.

The biggest gains in April came in education, health services, and leisure and hospitality. The biggest job losses were in professional and business services. Public-sector employment was also down.

Overall, New Jersey still has 54,000 fewer jobs than it did in 2008.

In southern New Jersey, the labor market has remained weaker than the state as a whole.

For March, the latest county-level data available, the seasonally adjusted unemployment rate for Atlantic County was 13.1 percent, according to figures provided by the Federal Reserve Bank of Philadelphia.

It was 13.2 percent in Cumberland County and 12.7 percent in Cape May County.

Unemployment is shaping up as a major issue in this year’s gubernatorial race.

Christie, a Republican, is expecting to face Democratic state Sen. Barbara Buono in the gubernatorial race. She’s been critical of his record on jobs creation, largely because New Jersey is lagging behind the country as a whole.

The U.S. unemployment rate for April was 7.5 percent.

Staff Writer Brian Ianieri contributed to this report