Frequencies for first 10,000 rows of urf_incerv variable in natlterr2006 dataset :

Incompetent |
 cervix RFP |
691=f_urf_i |
  ncervix U |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          1        0.01        0.01
          2 |      4,795       47.95       47.96
          9 |      1,479       14.79       62.75
          . |      3,725       37.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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