Frequencies for first 10,000 rows of ageflag variable in namcs2013 dataset :

      Was patient age |
   calculated by NCHS |
          during data |
        processing or |
  recorded on instrum |      Freq.     Percent        Cum.
----------------------+-----------------------------------
    Birthdate imputed |         17        0.17        0.17
   Calculated by NCHS |      9,751       97.51       97.68
Entered by respondent |        232        2.32      100.00
----------------------+-----------------------------------
                Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Mar 2017