Frequencies for first 10,000 rows of uca_spina variable in linkpe2009psden dataset :

      Spina |
bifida/Meni |
ngocele U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          2        0.02        0.02
          2 |      9,930       99.30       99.32
          9 |         68        0.68      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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