A) The selected 739 genes (see text) were grouped according to ORF length. Each group contained at least 85 genes. For each length-group, the fraction of genes in that group containing 1-3 ribosomes (dark blue) 4-5 ribosomes (light blue), 6-8 ribosomes (green) and 9 or more ribosomes (brown) is shown. B) The number of genes as a function of ribosome density (Average = 0.64 + 0.31 ribosomes/100 nts). C) Ribosome density as a function of ORF length (open circles). The red line indicates moving average density value (window of 50). The ordering of the density values (open circles) in apparent hyperbolic curves arises because the ORF lengths are divided by quantized values (whole number of ribosomes).