Frequencies for first 10,000 rows of ume_vac variable in linkpe2009psden dataset :

 Vacuum U;R |
(f_u_vacuum |
  rep flag) |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        129        1.29        1.29
          2 |      9,819       98.19       99.48
          9 |         52        0.52      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015