[T]he upper 10 percent of the labor income distribution generally receives 25-30 percent of total labour income, whereas the top 10 percent of the capital income distribution always owns more than 50 percent of all wealth (and in some societies as much as 90 percent). Even more strikingly, perhaps, the bottom 50 percent of the wage distribution always receives a significant share of total labor income (generally between one-quarter and one-third, or approximately as much as the top 10 percent), whereas the bottom 50 percent of the wealth distribution owns nothing at all, or almost nothing (always less than 10 percent and generally less than 5 percent of total wealth, or one-tenth as much as the wealthiest 10 percent). Inequalities with respect to labor usually seem mild, moderate, and almost reasonable (to the extent that inequality can be reasonable – this point should not be overstated). In comparison, inequalities with respect to capital are always extreme.
Piketty, Thomas (Translated by Arthur Goldhammer). Capital in the Twenty-First Century. 2014. p. 244 (hardcover)