Frequencies for first 10,000 rows of cityres variable in natl1975 dataset :

  NCHS City |
         of |
  Residence |      Freq.     Percent        Cum.
------------+-----------------------------------
        018 |          1        0.01        0.01
        021 |      1,007       10.07       10.08
        069 |          1        0.01       10.09
        078 |          1        0.01       10.10
        087 |          1        0.01       10.11
        096 |          1        0.01       10.12
        156 |          1        0.01       10.13
        276 |          1        0.01       10.14
        291 |          1        0.01       10.15
        999 |      8,985       89.85      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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