Frequencies for first 10,000 rows of avglosf variable in nsrd dataset :

  Average Global Horizontal Source Flag |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
I - Modeled solar radiation data using  |        798        7.98        7.98
J - Modeled solar radiation data using  |      9,202       92.02      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016