Frequencies for first 10,000 rows of blodpres variable in namcs2001 dataset :

      blood |
   pressure |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,509       65.09       65.09
          1 |      3,491       34.91      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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