Frequencies for first 10,000 rows of ndclength variable in ndc2lblprodcodexw dataset :

 Length NDC |      Freq.     Percent        Cum.
------------+-----------------------------------
          9 |      9,998       99.98       99.98
         10 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 11 May 2018