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

hematocrit/ |
 hemoglobin |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,711       97.11       97.11
          1 |        289        2.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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