By 1914, millions of immigrants from eastern and southern Europe were doing the dirtiest, most dangerous jobs in America's mines, mills and factories. The next decade saw major economic and demographic changes and the indoctrination of immigrant populations with labor movement ideology from both the U.S. and Europe. From the bottom rungs of the industrial hierarchy, immigrants pushed forward the greatest wave of strikes in U.S. labor history-lasting from 1916 until 1922-while nurturing new forms of labor radicalism. In response, government and industry, supported by deputized nationalist organizations, launched a campaign of ""100 percent Americanism,"" developing new labor and immigration policies that culminated in the 1924 National Origins Act, which brought to an end mass European immigration. American industrial society would be forever changed.