sort nation
merge nation using nationcodes
This is the better way to do this, especially if the set of nations is
large. It embodies the notion that the mapping of nation to origin is an
entity in its own rite; it is data, not code. This is more
maintainable. Further, if you need to do it in several places, you need
only repeat the -merge- operation, rather than a long segment of
code. (That long segment of code could be made into a program, but I would
still prefer the -merge- method, on principle.)
