Frequencies for first 10,000 rows of pct012k144 variable in sf12010880us30 dataset :

   37 years |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,251       92.51       92.51
          1 |        589        5.89       98.40
          2 |        114        1.14       99.54
          3 |         25        0.25       99.79
          4 |         14        0.14       99.93
          5 |          4        0.04       99.97
          6 |          1        0.01       99.98
          7 |          1        0.01       99.99
         11 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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