Frequencies for first 10,000 rows of examwi2 variable in nhamcsopd2003 dataset :

       exam |
write-in #2 |
  - 4 digit |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,717       97.17       97.17
       8906 |          1        0.01       97.18
       8913 |          9        0.09       97.27
       8926 |         31        0.31       97.58
       8934 |         18        0.18       97.76
       8936 |         26        0.26       98.02
       8939 |        167        1.67       99.69
       9403 |          4        0.04       99.73
       9509 |         24        0.24       99.97
       9543 |          1        0.01       99.98
       9547 |          1        0.01       99.99
       9999 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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