Frequencies for first 10,000 rows of ume_vbac variable in natlterr2007 dataset :

    Vaginal |
      after |
  C-Section |
        RFP |
731=f_u_vba |
        c U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         58        0.58        0.58
          2 |      4,648       46.48       47.06
          9 |      1,457       14.57       61.63
          . |      3,837       38.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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