I put 9-15, because I know of this many. It's quite subjective though. For example, did they take up cycling only because of my example, or did others also inspire them? Also, who knows how many others may have taken up cycling because they simply saw me on the road.
One of my main incentives for cycling came from a gentleman in Minnesota, who appeared to be 50-60 years old. He had cycled all the way to St. Louis for a convention. In my early 30s at the time, I found this to be extremely inspirational. But he never knew that he was my inspiration.