Frequencies for first 10,000 rows of hematocr variable in nhamcsopd2004 dataset :

hematocrit/ |
 hemoglobin |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,509       95.09       95.09
        yes |        491        4.91      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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