Frequencies for first 10,000 rows of drugres3 variable in person dataset :

  DRUG TEST |
  RESULTS-3 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,733       97.33       97.33
          1 |         66        0.66       97.99
        177 |          1        0.01       98.00
        205 |          1        0.01       98.01
        304 |          1        0.01       98.02
        321 |          1        0.01       98.03
        351 |          3        0.03       98.06
        402 |          1        0.01       98.07
        407 |          2        0.02       98.09
        417 |          1        0.01       98.10
        423 |          1        0.01       98.11
        600 |          1        0.01       98.12
        603 |          2        0.02       98.14
        605 |          1        0.01       98.15
        606 |          1        0.01       98.16
        695 |          1        0.01       98.17
        996 |          7        0.07       98.24
        997 |          2        0.02       98.26
        999 |        174        1.74      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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