Frequencies for first 10,000 rows of exmwi22d variable in namcs2001 dataset :

       exam |
write-in #2 |
  - 2 digit |      Freq.     Percent        Cum.
------------+-----------------------------------
         00 |      9,647       96.47       96.47
         16 |          2        0.02       96.49
         89 |        339        3.39       99.88
         94 |          3        0.03       99.91
         95 |          6        0.06       99.97
         99 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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