A) A measure of non-random distribution termed a Clustering Factor (CF) is plotted in the most populated bin for 8-mers with at least 20 members in the most populated 20 bp bin (abundant 8-mers). Note the dots between -100 bp and the TSS with large CF values representing 8-mers that are more abundant near the TSS than elsewhere. B) A probability term P for the 8-mers in (A). A P value of 24 means that the distribution of the 8-mer has a less than 10-24 chance of being random. C) Non-random distribution of 8-mers (Clustering Factor) vs. 8-mer-association-with-RNAP for abundant 8-mers.