Maine’s lone 207 area code is projected to last more than two years longer than previously thought, extending through the summer of 2036.

The state Public Utilities Commission announced the projection on Wednesday, citing findings from a review by the North American Numbering Plan Administrator. The last forecast, made in April, said numbers with the Maine area code would be depleted by the end of 2033.

Maine is one of 11 states with one area code, according to the agency that assigns area codes for the U.S. and Canada.

The 207 code dates to 1947. It was designed when there was greater emphasis on geographical areas with toll calls for in-state and out-of-state long-distance calls and when one monopoly telephone service provider managed local and long-distance calls, state utility regulators said in a report issued last week.

Greater competition and cell phone technology have transformed telecommunications and as a result, the number of service providers in Maine “far exceeds what the architects of Maine’s original numbering plan for 207 could ever have envisioned,” the report said.

There are about 8 million usable 207 telephone numbers, according to the PUC.

The commission has been monitoring for several years the area code that serves Maine “as the number of service providers in Maine has been increasing significantly along with the volume of numbering requests.”

Chairman Philip L. Bartlett II, calling the PUC’s work “conservation efforts,” said it’s working with companies to make sure they get the telephone numbers they need and asking businesses to return numbers they don’t need.

To maximize the availability of numbers, the PUC is making certain that service providers are “promptly and properly returning unused or under-utilized blocks” of number to the 207 numbering pool.

“These efforts have led to the return of 750,000 numbers to the numbering pool,” the report said.

The PUC said it’s working with the North American Numbering Plan Administrator, the Federal Communications Commission and state lawmakers to curb robocalling with numbers sold to companies by telephone providers.

The numbering agency says about 37% of the available 207 numbers are being used, but it also forecasts that 207 is in “imminent danger of exhaustion,” the PUC report said. The reason for this apparent discrepancy is service providers’ anticipated needs for future numbers.

If an area code is close to running out of unused numbers in a “numbering pool,” the area code is said to be “exhausted,” according to the PUC report. Using up an area code is caused by assigned and in-service use of telephone numbers, numbers that are in the inventory of a service provider but are not in service because they are “spares” set aside for future customers and disconnected customer numbers that need to remain unused for a minimum amount of time, the PUC report said.

The PUC last year began looking into “Rate Center Consolidation” that would combine 149 calling areas into one. The result would reduce demand for numbering resources. The PUC said it’s wrapping up the review.

In comments to the PUC, Charter Communications said it has participated in rate center consolidations within its 41-state network and the “scale of those efforts has been modest compared to the Maine proposal.”

The so-called “exhaust date” of the 207 area code has been pushed back many times. In January 2021, forecasters projected it would expire in 2024. It gets updated every six months.