Well, if the migrant sub-population of humans tends to seek out opportunities, then it would make sense that the poll might seem US centric as it has been the most prosperous state over the last 50-60 years. That said, if such a migrant sub-population does exist, it would also be interesting to know if they are still arriving/settling in the US, or whether they have a new destination in mind...

In that case you should be also asking why people emigrated. I emigrated from the UK to the US and although I now consider myself an aspiring entrepreneur I emigrated entirely for personal reasons.