Human Capital
Nick Schulz has an interesting introduction to recent work on immigration and human capital that includes this figure:
The human capital stock is probably over-estimated since it imputes the value of non-market time at market wages but even counting non-market time at zero (not correct either) would give a human capital stock of $212 trillion, about 5 times the physical capital stock. Thinking about human capital reminds us that debates about immigration and education are debates about investment.