Frequencies for first 10,000 rows of blodpres variable in namcs1994 dataset :

      blood |
   pressure |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      3,344       33.44       33.44
          1 |      6,656       66.56      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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