Frequencies for first 10,000 rows of ageflag variable in namcs2012 dataset :

      Was patient age |
   calculated by NCHS |
          during data |
        processing or |
  recorded on instrum |      Freq.     Percent        Cum.
----------------------+-----------------------------------
    Birthdate imputed |         38        0.38        0.38
   Calculated by NCHS |      9,810       98.10       98.48
Entered by respondent |        152        1.52      100.00
----------------------+-----------------------------------
                Total |     10,000      100.00

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