Frequencies for first 10,000 rows of uca_ompha variable in natl2005 dataset :

Omphalocele |
/Gastroschi |
    sis U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          4        0.04        0.04
          2 |      9,856       98.56       98.60
          9 |        140        1.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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