H i column density distribution for re-measured DR9 DLAs initially identified with log N(H i) ≥ 21.2 and Δv ≤ 3000  km  s^-1. Cyan shading indicates DLAs that reveal narrow Lyα emission. The sample is complete above log N(H i) = 21.3 (red arrow), and systems with lower column densities are not included in the statistical sample. One log N(H i) ≥ 21.3 DLA (marked with cross-hatching) is also not included in the statistical sample because of the velocity difference between the DLA and the quasar.