Frequencies for first 10,000 rows of pct012k021 variable in sf12010880us30 dataset :

   18 years |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,071       90.71       90.71
          1 |        699        6.99       97.70
          2 |        148        1.48       99.18
          3 |         37        0.37       99.55
          4 |         28        0.28       99.83
          5 |          8        0.08       99.91
          7 |          2        0.02       99.93
          8 |          1        0.01       99.94
          9 |          2        0.02       99.96
         10 |          2        0.02       99.98
         11 |          1        0.01       99.99
         36 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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