Frequencies for first 10,000 rows of prov0465 variable in pos1999 dataset :

experimenta |
 l research |
  conducted |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,979       99.79       99.79
          Y |         21        0.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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