Frequencies for first 10,000 rows of on_prol variable in natl2013 dataset :

  Prolonged |
  Labor RFP |
607=f_on_pr |
    olong R |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,105       91.05       91.05
          U |        479        4.79       95.84
          Y |        416        4.16      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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