NASCAR and the South

For most of its history, NASCAR as been considered a Southern sport, with all the best race tracks and all the best racers coming from the South, not to mention that most of its fan base was southerns. When I was looking around however, I saw that NASCAR has changed over the past decade. While reading this article I started to think of how many places had race tracks, and how many of them weren't actually in what most would qualify as the South. I wonder, although these races weren't always taking place in the South, nor that every driver was Southern, is NASCAR still considered a Southern sport because its audience base is still in the South, or does it make it a more national sport? Has NASCAR every truly been just a southern sport? What are your thoughts?