Shown are the fractions of alternative codes for which the average of the logarithm of the probabilities of all n-mers is equal or higher to that of the real code. Also shown are the fraction of alternative genetic codes for which the average probability of the 20% most-difficult n-mer sequences is equal or higher than in the real genetic code. Similar results are obtained for larger fractions of the most difficult n-mer sequences. Results for n > 8 are based on 10⁵ randomly sampled n-mers.