Linear data is measured using logarithmic scale (..., 0.1, 1, 10, 100, ...).<p>If you saw logarithmic scale ( <a href="http://www.ieer.org/log.gif" rel="nofollow">http://www.ieer.org/log.gif</a> ), you know that distance between 1 and 2 on logarithmic scale is much wider than between 2 and 3, and so on. So, no surprise, if you seed linear data through logarithmic (non-linear) filter, then numbers will follow pattern of logarithmic scale.