Frequencies for first 10,000 rows of therpr23 variable in namcs2000 dataset :

      other |
  ther/prev |
 service #2 |
    - 3 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,994       99.94       99.94
        487 |          1        0.01       99.95
        935 |          1        0.01       99.96
        937 |          1        0.01       99.97
        940 |          1        0.01       99.98
        944 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016