Frequencies for first 10,000 rows of omphalo variable in natl1997 dataset :

Omphalocele |
/Gastroschi |
        sis |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          4        0.04        0.04
          2 |      9,984       99.84       99.88
          9 |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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