Frequencies for first 10,000 rows of prov0465 variable in pos2004 dataset :

experimenta |
 l research |
  conducted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,961       99.61       99.61
          Y |         39        0.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016