+1 phone numbers not syncing with contacts

I have a lot of contacts saved in my address book that sync with my iPhone. I haven't stored any of my contacts with a 1 in the beginning of the number, so every time I get a phone call or text, even from a contact, it only displays the phone number with a 1 in front of it. It is really annoying because I have to search my contact list to find who it is, then add the phone number with a 1. Is there any way to avoid having to do this? Can I make my iPhone recognize numbers without the obligatory 1? My regional settings are to United States.