Frequencies for first 10,000 rows of incervix variable in natl1992 dataset :

Incompetent |
     cervix |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         10        0.10        0.10
          2 |      9,964       99.64       99.74
          9 |         26        0.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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