All three countries (Canada , Mexico  and United States ) are posted.
So why bother ?
Well, political geography is not like money. It has no time value.
Governance is a "Mature Industry". They had the same product last week
as this week. Political power is defined the same way as classical
physics defines Power, as the derivative of Work with respect to Time.
That in turn means that political systems do work like a Carnot Cycle
(Engine) with an increase in Entropy (Open System). For example, a
Province of the Roman Empire has no "Power" because it does no work (any
more), and Kansas has "Power" because it does work, but does not get a
little bit bigger each night as you expect of your savings account.
These files are a framework for trade origins and destinations. You
should be able to extract the geo "categories" needed for a given task.
What would be real cool is if somebody wrote an XSLT which wrote a PERL
Script which created a list of directories, say on a thumb drive. This
would give you a filing system exactly the right size for the task,
with the idea that if you have to expand you are doing something wrong