Frequencies for first 10,000 rows of cityres variable in natl1987 dataset :

  NCHS City |
         of |
  Residence |      Freq.     Percent        Cum.
------------+-----------------------------------
        004 |          1        0.01        0.01
        008 |        532        5.32        5.33
        010 |          2        0.02        5.35
        021 |        494        4.94       10.29
        023 |        700        7.00       17.29
        024 |        490        4.90       22.19
        030 |          1        0.01       22.20
        032 |          1        0.01       22.21
        033 |          1        0.01       22.22
        047 |          1        0.01       22.23
        999 |      7,776       77.76       99.99
        ZZZ |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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