Frequencies for first 10,000 rows of ume_vbac variable in natlterr2008 dataset :

    Vaginal |
      after |
  C-Section |
        RFP |
731=f_u_vba |
        c U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         71        0.71        0.71
          2 |      4,575       45.75       46.46
          9 |      1,415       14.15       60.61
          . |      3,939       39.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016