In reply to Sara A,.

Most statisticians (for example, Silverman (1986), "Density Estimation") define histograms as the counts of fixed-width bins. To create a graph of the number of counts for unequal bins, it is best to use a bar chart. If you have already run the code in this blog, you can create the bar chart by running
call bar(lbls) freq=Freq;

Outside of SAS/IML, you can use PROC FORMAT to define a format and then use PROC FREQ to tabulate the data and draw the bar chart. If you don't know how to use PROC FORMAT or PROC FREQ, post a question to the SAS Statistical Procedures Community.