15.22.6  LIMITED 

You  may  specify  the limits over which the histograms are to be divided.
If you specify the Y or Z limits,  then  all  data  that  contains  values
inside these limits will be divided.  For example if you
     DIVIDE 1 by 2 LIMITED FROM Y=10 to Y=11
But data set 1 contains the followind data:
1,0;  2,10;  3,0;  4,11;  5,0
Points  2  to 4 inclusive will be divided, and only points 1 and 5 will be
omitted.