That is incorrect. The shares of Khosla Ventures and Sequoia Capital are shown both in the "5% Stockholders" and again shown in the "Executive Officers and Directors" section since both firms also hold seats on the board. Also, investors holding <5% stake are not represented.

The real math is 33.6% to investors holding a >5% stake, 38.8% to execs & directors, and 27.6% not represented (probably a mix of investors and the employee option pool)