Quаntity (milliоns оf students per yeаr) Mаrginal private benefit (thоusands ofdollars per student per year) Marginal social benefit (thousands of dollars per student per year) Marginal private cost (thousands of dollars per student per year) 4 20 28 8 8 18 25 10 12 16 22 12 16 14 19 14 20 12 16 16 24 10 13 18 The table above shows marginal costs and benefits of college education. The efficient level of enrollment is