In 2009, a study by the Cato Institute, a free market think tank, found that legalization of low-skilled illegal resident workers in the US would result in a net increase in US GDP of $180 billion over ten years. The Cato Institute study did not examine the impact on per capita income for most Americans. Jason Riley notes that because of progressive income taxation, in which the top 1% of earners pay 37% of federal income taxes (even though they actually pay a lower tax percentage based on their income), 60% of Americans collect more in government services than they pay in, which also reflects on immigrants. In any event, the typical immigrant and his children will pay a net $80,000 more in their lifetime than they collect in government services according to the NAS. Legal immigration policy is set to maximize net taxation. Illegal immigrants even after an amnesty tend to be recipients of more services than they pay in taxes. In 2010, an econometrics study by a Rutgers economist found that immigration helped increase bilateral trade when the incoming people were connected via networks to their country of origin, particularly boosting trade of final goods as opposed to intermediate goods, but that the trade benefit weakened when the immigrants became assimilated into American culture.