[Drysnyaty]

Not income, gents.

As income includes transfer payments, bonuses, and commissions which are irrelevent to 80% of workers (See: Wallace Peterson's 'The Silent Depression').
I am talking real-wages, which are down 17-30% since 1973.

See 'The Myth of Free Trade' and BLS data.

Also google 'real wages fall since 1973'.

Joao,
Earned income is defined as wages, compensation, bonuses, tips, and self employment income. Unearned income includes transfer payments, capital gains, interest, dividends, alimony, unemployment compensation, pension, annuities, ira's, rental income, other passive activity income, and all other income not easily identifiabel. Farm income can be considered either earned or unearned, depending on your activities. S corp, partnership share, etc is also considered either earned or passive depending on the how the income was derived by the pass through entity. However, using IRS data does neither confirm nor deny that real wages have declined or increased. BLS data and NBER research are the best possible analysis to confirm the theory, not the book you described.