Wow, great charts.

I have a few questions:

How close do you think the total 60k hosts is to the actual number of hosts. Is it even possible to be certain that you counted the vast majority (ie. 99%) of active hosts?

In the chart depicting the number of hosts in each country, you list "other" as a category. Does this category of around 10,500 hosts consist of other countries and unknown locations or just other countries?