Frequencies for first 10,000 rows of ume_vbac variable in natlterr2003 dataset :

    Vaginal |
      after |
  C-Section |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         61        0.61        0.61
          2 |      9,912       99.12       99.73
          8 |         23        0.23       99.96
          9 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015