Frequencies for first 10,000 rows of prov6210 variable in pos2008 dataset :

       srv: |
   magnetic |
  resonance |
    imaging |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,655       86.55       86.55
          0 |      1,173       11.73       98.28
          1 |         87        0.87       99.15
          2 |         71        0.71       99.86
          3 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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