Frequencies for first 10,000 rows of cityres variable in natl1979 dataset :

  NCHS City |
         of |
  Residence |      Freq.     Percent        Cum.
------------+-----------------------------------
        012 |          1        0.01        0.01
        021 |        657        6.57        6.58
        030 |          3        0.03        6.61
        048 |        302        3.02        9.63
        054 |        419        4.19       13.82
        057 |        423        4.23       18.05
        075 |          1        0.01       18.06
        087 |          1        0.01       18.07
        471 |          1        0.01       18.08
        999 |      8,191       81.91       99.99
        ZZZ |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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