Frequencies for first 10,000 rows of ume_vac variable in natlterr2003 dataset :

 Vacuum U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         43        0.43        0.43
          2 |      9,930       99.30       99.73
          8 |         23        0.23       99.96
          9 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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