Frequencies for first 10,000 rows of ume_vbac variable in natl2003 dataset :

    Vaginal |
      after |
  C-Section |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        156        1.56        1.56
          2 |      9,815       98.15       99.71
          8 |          5        0.05       99.76
          9 |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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