Frequencies for first 10,000 rows of spina variable in natl1989 dataset :

      Spina |
bifida/Meni |
    ngocele |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          5        0.05        0.05
          2 |      9,758       97.58       97.63
          9 |        237        2.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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