Frequencies for first 10,000 rows of seen72 variable in nhamcsed2009 dataset :

    seen in |
    this ed |
 within the |
    last 72 |
     hours? |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |        268        2.68        2.68
         -8 |        869        8.69       11.37
          1 |        369        3.69       15.06
          2 |      8,494       84.94      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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