Slightly more Long Island manufacturers are optimistic about the economy now than in November, according to a survey released Monday.

Fifty-one percent of factory executives predicted an increase in new orders in the second half of 2016. That’s an improvement over late last year, when 45 percent said they expected more orders.

Just 6 percent of executives surveyed in Nassau and Suffolk counties said orders would decline, while 43 percent said they would hold steady.

The results came from a poll of 200 plant officials conducted May 10-27. The poll is the basis of the Purolator International Long Island Supply Chain Index, which debuted earlier this year.

“There’s growing optimism, but it’s not a dramatic change from the November survey,” said Leonie Huddy, the Stony Brook University political scientist who designed and analyzed the poll. “Things are moving forward, but not rapidly.”

The supply chain index focuses on manufacturing executives’ predictions about inventory levels, new orders and production activity over the next six months.

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Huddy said survey responses were converted to numbers to come up with an overall index of 60.6 points. No index number was calculated for the first poll, in November 2015.

An index above 50 points indicates economic growth, while a number below 50 indicates economic decline, she said.

In terms of hiring, 17 percent of those polled said they planned to increase payrolls later this year, while 5 percent said they would cut employees. The question wasn’t asked in November.

Purolator International president John T. Costanzo said some factories took on more workers last year in anticipation of higher sales and now don’t need to do further hiring.

“Companies don’t want to be overstaffed,” he said. “I don’t see these results as a negative.”

Costanzo also said the poll found 37 percent of local manufacturers are exporting, with Canada being the top destination.

The index is Costanzo’s brainchild and Jericho-based shipping giant Purolator International pays for the polls, which are conducted by Princeton Survey Research Associates International. The poll has a margin of error of plus or minus 7 percentage points.