Frequencies for first 10,000 rows of pct012k024 variable in sf12010880us30 dataset :

   21 years |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,111       91.11       91.11
          1 |        635        6.35       97.46
          2 |        155        1.55       99.01
          3 |         54        0.54       99.55
          4 |         17        0.17       99.72
          5 |          9        0.09       99.81
          6 |         11        0.11       99.92
          7 |          2        0.02       99.94
          8 |          3        0.03       99.97
          9 |          1        0.01       99.98
         12 |          1        0.01       99.99
         31 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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