Frequencies for first 10,000 rows of incervix variable in natl1995 dataset :

Incompetent |
     cervix |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         11        0.11        0.11
          2 |      9,946       99.46       99.57
          9 |         43        0.43      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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