Frequencies for first 10,000 rows of uca_ompha variable in natl2007 dataset :

Omphalocele |
/Gastroschi |
    sis RFP |
761=f_uca_o |
 mphalo U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          4        0.04        0.04
          2 |      9,099       90.99       91.03
          9 |        897        8.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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