If the RTINCLUDE option is specified on a HISTOGRAM statement in PROC UNIVARIATE and the bin endpoints are integer values, then data values of zero will be incorrectly plotted in one of two ways. If the MIDPOINTS= or ENDPOINTS= option is also specified such that the leftmost bin's lower endpoint is greater than or equal zero, and if the smallest data value is zero, PROC UNIVARIATE fails to extend the left axis to include zero values and they will be omitted from the plot. Or, if there are one or more data values less than zero, the left axis will be extended as necessary to include them, but any zero data points will be incorrectly plotted in the bin with the left endpoint of zero instead of in the bin with the right endpoint of zero.

There is no workaround for this problem in PROC UNIVARIATE. If SAS/QC^® is available, then PROC CAPABILITY can be used instead.