After the remaining valid area codes were used up by expansion, in 1995 the rapid increase in the need for more area codes forced the NANPA to allow the digits 2 through 8 to be used as a middle digit in new area code assignments, with 9 being reserved as a "last resort" for potential future expansion. At the same time, local exchanges were allowed to use 1 or 0 as a middle digit. The first area codes without a 1 or 0 as the middle digit were area code 334 in Alabama and area code 360 in Washington, which both began service on January 15, 1995. This was quickly followed by area code 520 serving Arizona on March 19, 1995.