For decades, new area codes were created through a "split" of an existing area code into multiple regions. Normally, the more populated region would continue to use the existing area code. The less populated areas would have all existing phone numbers reassigned to use a new area code to free up more numbers in the original area code. This process forced many into a new phone number which would require updates to letterhead, business cards, phone directories, personal contact lists, etc. Many people would dial the incorrect area code which caused confusion. In 1992, area code 917 was created as the first "overlay" area code. With an overlay area code, the overlay serves the same geographic as the original to increase the pool of numbers available in the area. When the original phone systems were put in place, 7-digit dialing (without the area code) could be used to make local calls, and 10-digit dialing (with the area code) only needed to be used for long distance calls. In 1997, area code 301 was introduced as the first overlay with forced 10 digit dialing for local calls. Initially, there was substantial public resistance to overlays because of the 10-digit dialing requirement for local calls. However, the last area code split in Canada was in 1999 with the split of 403 splitting off 780 and the last area code split in the US was in 2007 with 505 splitting off 575. No area code splits are currently proposed and both countries have agreed: without exceptional circumstances, all new area codes will be overlays. Today, 7-digit dialing is broken in most major cities. The few major cities where 10-digit dialing is not required include Detroit, El Paso, Jacksonville, Louisville, Memphis, Milwaukee and Oklahoma City. Many areas not served by an overlay can still use 7-digit dialing.