32 years ago on February 4th, 1992
Area code 917 is introduced, originally used only for cell phones
It was the first area code to be introduced overlapping an existing area code, and although primarily used for cell phones and pagers, it is now occasionally assigned to landlines in Manhattan due to the shortage of 212 numbers.
New York's most recent area code is 332, which was assigned to Manhattan in 2017. As of April 2020, NANPA, the organization in charge of assigning area codes, estimates that New York City's available phone numbers will begin to be completely depleted by 2030, although those estimates have been increasing as fewer new numbers have been needed in recent years. With the shift toward mobile phones and the portability of numbers, New York area codes can now travel across the country, bringing along the legacy of having once been assigned to someone living in New York City.
References: