Frequencies for first 10,000 rows of ume_repec variable in natl2007 dataset :

     Repeat |
  C-Section |
        RFP |
733=f_u_rep |
       ec U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        664        6.64        6.64
          2 |      9,277       92.77       99.41
          9 |         59        0.59      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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