Frequencies for first 10,000 rows of prov2200 variable in pos2006 dataset :

       srv: |
 laboratory |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      7,794       77.94       77.94
          0 |      1,414       14.14       92.08
          1 |         99        0.99       93.07
          2 |        639        6.39       99.46
          3 |         54        0.54      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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