[rdtsc]

Normally these are collected along the way while "moving on up in the world". Start in some poor country. Get citizenship in another slight better country and so on. Now "better" is subjective and defined by the individuals. For example, most people would consider Belize better than South Sudan.

Some just optimize based on the most travel permissive citizenships. Like, say the British passports let you in quite a few countries without a visa, so does an US passport but the countries are different.