Frequencies for first 10,000 rows of formtype variable in nhamcsopd2001 dataset :

      which |
 version of |
    patient |
record form |
      used? |      Freq.     Percent        Cum.
------------+-----------------------------------
          A |      4,260       42.60       42.60
          B |      5,740       57.40      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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