 Research on a migration lottery that allowed Tongans to move to New Zealand found that the lottery winners saw a 263% increase in income from migrating (after only one year in New Zealand) relative to the unsuccessful lottery entrants.A longer-term study on the Tongan lottery winners finds that they "continue to earn almost 300 percent more than non-migrants, have better mental health, live in households with more than 250 percent higher expenditure, own more vehicles, and have more durable assets".A conservative estimate of their lifetime gain to migration is NZ$315,000 in net present value terms (approximately US$237,000).