Well, yes and no. Unclear what countries, languages, etc. they are including in here. Your site's audience may in fact not represent the general population, so you could be optimizing for the wrong group.

It would be helpful to be able to see these %age borders for just US surfers, for example, or from US daytime usage vs. nightime, or even IPs resolving to corporate vs. non corporate (poor attempt at separating at work from at home usage). This way you could optimize for your intended audience instead of the general populace, few of whom might be your paying customers.

Wouldn't the most pertinent stats actually be your own stats from your own analytics?