I think the metric depend on the network of sites that provide the metric. So a lake of suffisent input from popular website of a country could bias result for

I think the metric depend on the network of sites that provide the metric. So a lake of suffisent input from popular website of a country could bias result for such a country. And a shift in the network could result on a shift on the data. The question that remain is was is more accurate before or does this shift result of a better accuracy.