Frequencies for first 10,000 rows of cntyres variable in natlterr1994 dataset :

NCHS County |
         of |
  Residence |      Freq.     Percent        Cum.
------------+-----------------------------------
      22000 |          1        0.01        0.01
      31000 |          2        0.02        0.03
      47000 |          1        0.01        0.04
      52011 |        563        5.63        5.67
      52013 |        372        3.72        9.39
      52016 |        432        4.32       13.71
      52050 |        256        2.56       16.27
      52058 |        561        5.61       21.88
      52065 |      1,170       11.70       33.58
      52999 |      6,630       66.30       99.88
      53999 |          8        0.08       99.96
      55ZZZ |          1        0.01       99.97
      59ZZZ |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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