Frequencies for first 10,000 rows of prov2200 variable in pos1999 dataset :

       srv: |
 laboratory |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      7,936       79.36       79.36
          0 |      1,245       12.45       91.81
          1 |        133        1.33       93.14
          2 |        665        6.65       99.79
          3 |         21        0.21      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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