by the time the tax forms are mailed out the GDP/head for the previous year has been computed.

I can see the advantages of that.  But what portion of GDP does total national wages form? Can I presume that the individuals income would be all income, including dividends, investment income, etc?

In the US we need to put high taxes on large estates as well.  As Willie Sutton observed: "Cause that is where the money is."

As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."