Frequencies for first 10,000 rows of crosswalklevel variable in planxw2015 dataset :

  Crosswalk |
      Level |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      5,727       57.27       57.27
          1 |      4,051       40.51       97.78
          2 |        183        1.83       99.61
          4 |         39        0.39      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 9 Dec 2017