OMAHA, Neb. — A monthly survey of business supply managers released Monday suggested the economy continues to grow in nine Midwest and Plains states, but an economist said the spreading coronavirus outbreak could soon threaten that growth.

The Mid-America Business Conditions index jumped to 57.2 in January from 50.6 in December, the survey report said. The November figure was 48.6. The January figure was the highest since March 2019.

The report said the jump, plus January's signing of the U.S.-Mexico Canada Agreement on trade and the "phase one" trade agreement with China, bodes well for the regional manufacturing economy. However, the survey was conducted before much of the bad news about the coronavirus outbreak that originated in China was reported.

"The negative impacts from this virus could place significant negative pressure on the regional economy in the weeks ahead," said Creighton University economist Ernie Goss, who oversees the survey.

The survey results are compiled into a collection of indexes ranging from zero to 100. Survey organizers say any score above 50 suggests growth. A score below that suggests decline. The survey covers Arkansas, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, Oklahoma and South Dakota.

Missouri's overall index rose to 56.2 from December’s 50.5. Average hourly wages for private workers in Missouri rose by 3.5% over the past 12 months, the report said.

"Nondurable-goods manufacturers are expanding at a solid pace, while durable-goods producers are experiencing pullbacks in economic activity," said Goss.

The regional trade numbers were mixed, according to the report. The index for new export orders soared to 52.1 from December's weak 43.5. The regional imports index sank to 46.3 from December's 52.0.

The two new trade agreements boosted the regional business confidence, however. The index rose to 58.8 from December's 57.6.

The January employment index increased to 53.8 from December's four-year low of 45.6. In past months, job growth was held in check by the trade constraints and the lack of available workers.

"January's positive employment reading was a positive and unexpected outcome," Goss said.