Much of the data is just wrong, clearly misinterpreting the relative independence of different places. Probably really quite a lot of it, since the spot-checks I've been able to do at a glance have found a bunch of issues.
Here we have Czechoslovakia being treated as part of the USSR after the Prague Spring (no, still in the Warsaw Pact), South Vietnam in 1970 as a direct US territory (nope!), Scotland in 1616 labelled as England, and San Marino apparently losing independence in 1799.








