> Standard of living is not identical with the percentage of national income you have.
I totally agree and didn't mean to imply this. My point is that the median income level as an absolute, adjusted for inflation, has not increased significantly since 1970. I believe this does correlate fairly well to standard of living over the long term.
EDIT: Here's one source. Open to criticism. http://www.stanford.edu/class/polisci120a/immigration/Median...