1996. A split was deemed unfeasible due to the island's extremely dense population and the lack of a suitable boundary for a split. Additionally, a split would have forced half of Puerto Ricans to change telephone numbers for the second time in a decade. The first instance of a statewide overlay was West Virginia's area code 304, in 2009. West Virginia had been served by 304 since the inception of the North American Numbering Plan, but it was obvious by 2007 that the state needed a new area code. At first, state officials voted to split off northern West Virginia with area code 681 and to leave southern West Virginia in 304. However, lobbying by the telecommunications industry led the state to reverse the decision and turn 681 into an overlay. Idaho followed that precedent in 2017 by overlaying area code 208 with 986. Overlays gained popularity among Canadian telephone companies in the early 2000s, primarily as a workaround for the country's inefficient number allocation system. Every competing carrier is issued blocks of 10,000 numbers (corresponding to a single three-digit prefix) in each rate center in which it offers new service and each local interconnection region in which it ports existing numbers. While most rate centers in Canada do not need nearly that many numbers to service customers adequately, a number cannot be reassigned elsewhere once it is assigned to a carrier and rate center. This resulted in a large amount of unallocated numbers. The problem was exacerbated by the proliferation of cellphones, fax machines, pagers, and dial-up Internet connections, particularly in larger markets. Partly due to this, the area codes corresponding to four of the five largest Canadian markets (416 in Toronto, 514 in Montreal, 604 in Vancouver, and 403 in Calgary) were split in the 1990s. The number allocation problem manifested itself at the turn of the century in Metro Toronto and the Golden Horseshoe, the center of Canada's largest local calling area. This area had been served by 416 since the institution of the area code system. Despite the Golden Horseshoe's explosive growth in the second half of the 20th century, numbers in the region were used up fairly quickly. As a result, the number allocation problem was not as severe in 416 as it was in the rest of Canada. Nevertheless, it was severe enough to force Toronto's suburban ring into area code 905 in 1993.