Frequencies for first 10,000 rows of pct012k200 variable in sf12010880us30 dataset :

   93 years |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,953       99.53       99.53
          1 |         44        0.44       99.97
          2 |          2        0.02       99.99
          6 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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