Nice chart. However, it doesn't verify InAlienable's statement nor does it disprove my statement. Wages were flat before the undocumented worker population exploded.
I can't speak for someone else's claims but I think he's talking about under-the-table and blackmarket earnings which would be impossible to quantify.
But as far as wages being flat; if we're talking real wages as in your graph, they are supposed to stay flat or level assuming stable labor supply/demand. Real wages represent the adjusted for inflation purchasing power of nominal wage values so increases/decreases in real wages relative to consistent units of labor output would suggest a contraction/expansion of the money supply with deflation/inflation of the currency. In other words, fluctuations of real wages all else being equal are a troublesome sign of monetary volatility.
Receiving equivalent real value compensation for equivalent labor output over time is perfectly reasonable and efficient.