That's a nice resource but I don't think it shows what you intended it to show. From that timeline all I gather is that the United States has always wavered between xenophobia and the need for labor.
We are now in the fourth decade of an unprecedented experiment with extraordinarily high immigration. The length of this wave and the volume of newcomers dwarfs all previous waves. This is also the first experiment with high numbers of non-Westerners, who to all indications do not appear to be assimilating and intermarrying as previous waves did.
The lesson to take away from the history of American immigration is that immigration waves should be followed by long periods of zero immigration for assimilation.
http://www.numbersusa.com/content/learn/sustainability/bigge...