Frequencies for first 10,000 rows of seen72 variable in nhamcsed2015 dataset :

   Was patient |
  seen in this |
 ED within the |
 last 72 hours |
           and |
   discharged? |      Freq.     Percent        Cum.
---------------+-----------------------------------
         Blank |        116        1.16        1.16
       Unknown |        552        5.52        6.68
           Yes |        337        3.37       10.05
            No |      8,995       89.95      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 20 Nov 2017