Frequencies for first 10,000 rows of drugtst2 variable in person dataset :

  Drug Test |
  -Type (2) |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,415       94.15       94.15
          1 |        550        5.50       99.65
          2 |         19        0.19       99.84
          3 |          1        0.01       99.85
          6 |          1        0.01       99.86
          7 |          2        0.02       99.88
          8 |         11        0.11       99.99
          9 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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