How many Americans earning more than $400,000 will join French actor Gérard Depardieu and become Russian citizens?

Or put differently:

What would have to be a new threshold to make high-income earners seek new citizenship?

Here’s Gérard Depardieu’ story:

“A few hours after President Vladimir Putin signed a decree granting Gérard Depardieu Russian citizenship it was clear the French actor would have little difficulty making new friends in his adopted homeland. Offers of hospitality came flooding in from across Russia.

To be eligible for Russia’s 13% flat rate income tax, however, Depardieu would have to be resident in the country for at least six months of every year. But he was non-committal about whether he would move permanently to his new homeland.”

http://www.guardian.co.uk/film/2013/jan/04/gerard-depardieu-club-russian-citizens