Library /sys$common/syshlp/pca$help.hlb PLOT, Sorting qualifiers, /ASCENDING  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /ASCENDING[=n[:m]]

    Sorts the histogram in ascending order by bucket data count
    (smallest count first). If you specify =n, only the first n
    buckets (after sorting) are retained in the histogram. If you
    specify =n:m, only buckets n through m (after sorting) are
    retained.