Frequencies for first 10,000 rows of ume_vbac variable in natl2004 dataset :

    Vaginal |
      after |
  C-Section |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        153        1.53        1.53
          2 |      9,812       98.12       99.65
          9 |         35        0.35      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 21 Jan 2016