Frequencies for first 10,000 rows of hematocr variable in nhamcsopd1997 dataset :

hematocrit/ |
 hemoglobin |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,573       95.73       95.73
          1 |        427        4.27      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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