Output strengthened in 39 U.S. states in September from a month earlier, with some of the best gains concentrated in northeastern territories including Massachusetts, New York, and New Jersey, a Federal Reserve proxy showed.

Readings weakened in eight states, with the steepest drop in tourism-dependent Hawaii, and remained stable in three as the third quarter closed, according to the Philadelphia Fed’s State Coincident Indexes report released Friday.

Longer term, several states have almost fully rebounded back to their pre-pandemic levels. Nebraska, Utah and Missouri climbed back in September to within 1 percentage point of their February readings, while Georgia, Kentucky, Montana and Oklahoma were less than 2 points away.

The indexes combine four state-level indicators -- payroll employment, manufacturing hours worked, the jobless rate, and wages paid -- to summarize current economic conditions.

Over the past three months, the reserve bank’s national index has increased by 2.3% as 48 states showed improvement and just two saw declines: Hawaii and New Mexico.