Frequencies for first 10,000 rows of cleftlp variable in natl1991 dataset :

      Cleft |
 lip/palate |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         11        0.11        0.11
          2 |      9,980       99.80       99.91
          9 |          9        0.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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