Frequencies for d2_1_c1_4 variable in snf_rollup2540_96_1997 dataset :

  d2_1_c1_4 |      Freq.     Percent        Cum.
------------+-----------------------------------
         20 |          1        0.01        0.01
    5389763 |          3        0.03        0.03
          . |     11,914       99.97      100.00
------------+-----------------------------------
      Total |     11,918      100.00

by Jean Roth , jroth@nber.org , 17 Feb 2018