Do the numbers 551, 862 or 848 mean anything to you? It might be easy to guess that they are area codes, but determining which regions they represent is a tougher task. All three were created five years ago to serve northern New Jersey, but few people actually have them. Like other states, New Jersey’s area codes were rapidly being drained of phone numbers amid the proliferation of cell phones, pagers and fax machines. But a new pool of 23 million numbers has been barely tapped, with less than 2 percent of the new numbers assigned to customers. New Jersey’s experience is not unique. Despite growing demand for phone numbers, the need for new area codes sharply declined since 2001, as consumers dumped pagers for cell phones and new regulations cut down on wasted telephone numbers. In addition, the end of the telecommunications boom chased small startup companies from the phone market, freeing numbers those companies had hoped to provide. “These area codes are living longer,” said John Manning, director of the North American Numbering Plan Administration, which manages the registry of area codes, phone numbers and the database used by North American carriers to route calls. Indeed, the numbering administration has extended the projected “exhaustion” dates of nearly all 322 geographic area codes. Among the few estimated to be depleted earlier than expected are the 212 and 646 codes that serve Manhattan; 229 for Albany, Ga.; 254 for Waco, Texas; 309 for Peoria, Ill.; 702 for Las Vegas; 904 for Jacksonville, Fla. Among New Jersey’s nine area codes, 609 is first in line to run out of numbers, around 2010. Area codes were instituted in 1947, but exploded in the last four years of the 1990s, with the addition of 108 codes nearly one-third of today’s total. By contrast, the last four years saw the addition of just 11 area codes. The system got major relief in 2001 when number pooling was implemented, allowing carriers to get phone numbers in blocks of 1,000, instead of 10,000. Before then, technical issues that affected billing barred smaller blocks associated with a single exchange, or prefix, which are is the three digits after the area code. “You had these prefixes being assigned, you got 10,000 numbers, but you only assigned 1,000, stranding 9,000 numbers,” Manning said. After the rule change, “We were able to take that excess inventory that carriers had built, and allow other carriers to use it.” The numbering administration is now better positioned to handle continued appetite for new phone numbers, he said. “Even though you have paging falling off, you have new services coming on board, which are driving demand,” such as Internet phone calls, Manning said. That demand has resulted in a record 585 million U.S. phone numbers in use as of June 2005, according to the Federal Communications Commission. That’s up more than 6 percent from 2004, which was up more than 6 percent from 2003. Verizon Communications Inc., which provides local phone service in 28 states and has a national wireless network, is well aware of the hunger for numbers. “Consumers today typically have at least one cell phone,” Verizon spokesman Richard J. Young said. In addition, Internet phone and cable telephone providers both require phone numbers with area codes, as do home alarms and services such as GM’s OnStar service, he said.