Frequencies for first 10,000 rows of drugres2 variable in person dataset :

  DRUG TEST |
  RESULTS-2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,795       97.95       97.95
          1 |         22        0.22       98.17
        155 |          2        0.02       98.19
        177 |          3        0.03       98.22
        187 |          1        0.01       98.23
        208 |          1        0.01       98.24
        304 |          2        0.02       98.26
        316 |          1        0.01       98.27
        319 |          1        0.01       98.28
        321 |          6        0.06       98.34
        351 |         17        0.17       98.51
        401 |          8        0.08       98.59
        402 |          1        0.01       98.60
        407 |         11        0.11       98.71
        417 |         31        0.31       99.02
        603 |         19        0.19       99.21
        606 |          4        0.04       99.25
        695 |          1        0.01       99.26
        702 |          1        0.01       99.27
        996 |         20        0.20       99.47
        999 |         53        0.53      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016