A graph titled Immigration to the United notes. The x axis shows years in increments of one decade, from 1840 to 1920. The y axis shows number of new immigrants, from 0 to 1,200,000. A line connects diamonds on the chart, which appear as follows: 1840, 100,000; 1850, 400,000; 1860, 200,000; 1870, 400,000; 1880, 450,000; 1890, 450,000; 1900, 450,000; 1910, 1,100,000; 1920, 420,000. Immigration to the United States peaked around .
Between 1910 and 1920, immigration .
This was most likely due to .

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