Frequencies for first 10,000 rows of mrcnty variable in natlterr2008 dataset :

   Mother's |
  County of |
  Residence |
        U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,608       26.08       26.08
         10 |      3,455       34.55       60.63
         21 |        200        2.00       62.63
         25 |        126        1.26       63.89
         31 |        152        1.52       65.41
         97 |         71        0.71       66.12
        113 |        203        2.03       68.15
        127 |        396        3.96       72.11
        999 |      2,789       27.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016