Couldn't help notice the higher number of people between 20 and 30, then a sudden decline only to increase again in later years. In my case, I became a NASCAR fan in 1958 at the age of 22 and followed as much as someone living in New Jersey could follow when races were not broadcast and National Speed Sport News was delivered Thursday with results and articles of the previous weeks events.
Then in my late twenties, got married, bought a business and spend all my time being a husband, business owner and father and racing interest, though still there, was not as much of a priority. This changed again in my mid to late 40's when the children were grown and gone, our businesses had managers and other interests were replaced by racing. So the age-o-graph seems to fit many others and raises the questions of how many find other pursuits in their working years and then rekindle the interest later in time, how many never lose interest and how many are just coming aboard as the numbers increase by age bracket.
Just something to process. Or is it ......