How do you account for the 1970s to ~1998 period of time when there was practically no change but the immigrant population increased 3x? You can't plot two things together and then immediately make correlations between them. I wish it was that simple. Science would be a cake walk.
And I don't need to correct my math I used the difference in population between the points you were talking about versus the coordinating difference in wages and accounted for those in the work force.
I'm quite aware correlation does not mean causation. However there is strong correlation in those charts.
As far as the two points, the difference in immigrant population from 1970 until now is about 30 million. From 1970 to 1998ish is about 15 million. Immigrants went from about 4.5% of the population in 1970 to about 13% in 2010.
Maybe more to the point, wages are like any other service or product. Prices are always set at the margin. If there are 100 job openings for plumbers, but only 90 seeking work, the wages are likely to go up a lot more than 10%.
A good example - one not easily outsourced - is nurses.
http://content.healthaffairs.org/content/22/6/199.long
How high must RN wages rise in the future to end the RN shortage? We find that inflation-adjusted wages must increase 3.2–3.8 percent per year between 2002 and 2016, with wages cumulatively rising up to 69 percent, to end the shortage. Total RN expenditures would more than double by 2016.
Higher wages and increased nurse training are key ingredients in the effort to end the U.S. nurse shortage.
So I can't find data going all the way to 2016, but these charts and this article by the Fed clearly show the effect.
What I see here is a roughly 35% increase in income over 6 years driven by scarcity of labor - those years included the .com implosion and the market crash after 9/11.
Now here's the question for you.
Would this have happened if there were plenty of nurses around?
And what do you think that says about the effect of importing labor?
https://minneapolisfed.org/publications/fedgazette/send-more-nurses-stat