You can use the spouse's country of birth for a whole family’s employment-based green card filing if that country’s queue is moving faster. Example:  You are from India and working in the US on an H1B visa. Your US green card application has been filed by your employer in the EB2 category with a priority date of August 2014 which currently has a waiting time of more than 20 years. You get married to a girl from Pakistan and both are now living in the USA. You are in luck and can use the Rest of the world’s employment-based final action date, CURRENT, to file your green card. You immediately get into the fast-track green card lane just because of your lucky wife who was born outside India.