Frequencies for first 10,000 rows of ucr34 variable in mort1975 dataset :

      ucr34 |      Freq.     Percent        Cum.
------------+-----------------------------------
         10 |      3,336       33.36       33.36
         30 |      6,664       66.64      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015