I don't think the statistic as presented has much meaning, nor would it be easy to determine its accuracy in any real way. However, aromatic tobaccos, in general, outsell non-aromatics by a huge margin. Somewhere around 85% to 90% of tobacco produced and consumed in the US would be considered aromatic in the common perception of the word. Captain Black was, for many years, I don't know if it still is, the #1 selling tobacco in the world.
It's hard to model the figures into something meaningful. Aromatic smokers tend to consume more tobacco than non-aromatic smokers, which skews the analysis. My gut feeling is that if you include US pipesters who smoke both aromatic and non-aromatic tobaccos, the figure is probably closer to 90%, if not higher. Smokers of only aromatics would be somewhat lower.
In any case, exclusively non-aromatic smokers are in the minority. Les nailed it regarding self-selection in group dynamics. Enthusiasts, which would make up the majority of pipe club members (and forum members, for that matter) do not represent the population at large. Though it may seem strange to us, the majority of pipe smokers are just that. Even the readership of Pipes Magazine and its forum members, the largest population of its kind, represents only a single digit percentage of the overall pipe smoking community. We're just a bunch of weirdos.