When was divisions instituted in the NFL?

The NFL instituted divisions in 1990 as part of a significant reorganization to enhance the league's structure. This change included the formation of divisions within each conference, which allowed for a more streamlined playoff process and a clear framework for scheduling games. The introduction of divisions aimed to create a sense of rivalry and competition among teams by grouping them into geographical and performance-based clusters. This restructuring was also a response to the expansion of the league, leading to the current format of having both an American Football Conference (AFC) and a National Football Conference (NFC), each split into multiple divisions. The other years listed do not align with the official implementation of this divisional structure.