http://www.pewhispanic.org/2015/11/19/more-mexicans-leaving-...
I don't think you need >3x the annual median income (that's top 10%) for immigrants to benefit.
Economics research says high wage immigrants benefit while low wage immigrants benefit the natives on net, although it may harm some natives.
In my opinion, even if it may harm some natives, due to the poverty alleviating effects of immigration, we should open immigration to anyone who doesn't have a criminal record. This isn't that crazy, till 1914 in the U.S.:
"Generally, those immigrants who were approved spent from two to five hours at Ellis Island. Arrivals were asked 29 questions including name, occupation, and the amount of money carried. It was important to the American government that the new arrivals could support themselves and have money to get started. The average the government wanted the immigrants to have was between 18 and 25 dollars ($600 in 2015 adjusted for inflation). Those with visible health problems or diseases were sent home or held in the island's hospital facilities for long periods of time. More than three thousand would-be immigrants died on Ellis Island while being held in the hospital facilities. Some unskilled workers were rejected because they were considered "likely to become a public charge." About 2 percent were denied admission to the U.S. and sent back to their countries of origin for reasons such as having a chronic contagious disease, criminal background, or insanity."
(from https://en.wikipedia.org/wiki/Ellis_Island#Primary_inspectio... )
What I want is this minus the racism and disqualification for health problems except maybe for contagious diseases.