These results come from Gallup's Minority Rights and Relations survey conducted June 15-July 10, which included an expanded sample of blacks and Hispanics. This practice is often referred to as "oversampling," and allows for a closer look at attitudes and opinions of minority groups whose representation in the sample of a standard poll might otherwise be too small for statistical analysis. In 2013, the last time a comparable methodology was used with respect to this question, U.S. adults reported largely similar attitudes. Gallup has also asked this question in several instances in polls that did not include an oversample of Hispanic and black adults, most recently in June 2014.

The longer-term trends since 2001 are unmistakable: U.S. adults' support for increased immigration is gradually growing. In surveys conducted within a year of the 9/11 attacks, which were perpetrated by 19 individuals who immigrated into the country, near-majorities or outright majorities of U.S. adults said immigration levels should be decreased. But as the 2000s came to a close and the current decade has unfolded, support for decreasing immigration has gradually fallen, hitting one of its lowest levels this year. As the country has slowly shifted away from this position, the percentage saying immigration levels should increase has doubled -- from 12% in June 2002 to 25% today.
Preferences for changes in immigration levels vary considerably by the respondents' race or ethnicity. Hispanics -- half of whom say they are immigrants themselves -- are most likely to say immigration levels should be increased (36%), while non-Hispanic whites offer the least amount of support for that proposition (21%). Blacks fall in between the two, at 30%. Despite these differences, the overall trend is similar for all three groups. Support for allowing increased immigration levels hit a low ebb for all races/ethnicities in the years immediately after 9/11, and climbed to new or nearly new highs in 2015.
This year's Minority Rights and Relations survey includes a sample of 508 Hispanics, roughly half of whom report being born in the United States and half outside of it. Despite the differences in their country of birth, these two groups of Hispanics do not evince statistically meaningful differences on this question. For both groups, about a third say immigration should be kept at present levels, roughly another third voice a desire to see immigration levels increased and still another approximate third say immigration levels should be decreased.
Nearly three-fourths of U.S. adults say that, on the whole, immigration is a good thing for the country, a continued affirmation for a practice that has been a core feature of the American experience. While a majority of the country has always agreed with this proposition, the margin has sometimes been more tepid, with a bare 52% agreeing in 2002. Similar to the sentiment that immigration levels should increase, agreement that immigration is a good thing has gradually risen in the years after the 9/11 attacks. In the 2013 and 2015 surveys -- both of which included minority oversamples -- such agreement reached as high as Gallup has measured since it first asked the question in 2001.
Large majorities of whites (72%), blacks (70%) and Hispanics (81%) say immigration has been a good thing for the country.
Though the U.S. is one of history's great immigrant societies, there is no broad consensus among its citizens today on how or whether immigration levels should change. The current trends suggest that more U.S. adults believe immigration levels should increase than did so a decade ago, but that view still trails the percentage who want levels decreased or kept the same. The growing acceptance of increased immigration levels is evident across racial and ethnic lines, though again this is hardly the predominant position.
But even as the overall specifics may be the subject of continued debate, the notion that immigration is a good thing for the U.S. is something the public widely accepts.
Results for this Gallup poll are based on telephone interviews conducted June 15-July 10, 2015, with a random sample of 2,296 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia. All respondents had been previously interviewed in the Gallup Daily tracking survey and agreed to be recontacted by Gallup. For results based on the total sample of national adults, the margin of sampling error is ±4 percentage points at the 95% confidence level.
All reported margins of sampling error include computed design effects for weighting.

Source: Gallup