At the national level the balance of primary incomes makes gross income, i.e. before deduction of consumption of fixed capital, equal to Gross National Income (GNI).

UNESCO: Belarus: Report: Part I: Descriptive Section

By contrast, Americans overall reported less than 10% of their adjusted gross income as coming from capital gains.

FORBES: Taxes

The richest 400 reported 1.3% of all adjusted gross income but booked 8.5% of all net capital gains.

FORBES: Taxes