Frequencies for first 10,000 rows of pct012k031 variable in sf12010880us30 dataset :

   28 years |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,264       92.64       92.64
          1 |        565        5.65       98.29
          2 |        123        1.23       99.52
          3 |         27        0.27       99.79
          4 |         14        0.14       99.93
          5 |          4        0.04       99.97
          7 |          1        0.01       99.98
         15 |          1        0.01       99.99
         23 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 8 May 2017