Frequencies for first 10,000 rows of mrcnty variable in natlterr2007 dataset :

   Mother's |
  County of |
  Residence |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,686       26.86       26.86
         10 |      3,480       34.80       61.66
         21 |        225        2.25       63.91
         25 |        136        1.36       65.27
         31 |        172        1.72       66.99
         97 |         85        0.85       67.84
        113 |        204        2.04       69.88
        127 |        379        3.79       73.67
        999 |      2,633       26.33      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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