The PLOT command generates performance or coverage histograms.
    When you enter a PLOT command, you must specify two things: the
    kinds of data to tally, and how to partition the histogram. These
    two things define the meanings of the horizontal and vertical
    axes of the histogram. What kind of data to tally is specified
    with a data-kind qualifier (see qualifier list).

    Each histogram is partitioned into buckets representing value
    ranges. Each data point in the data file is tallied in the bucket
    whose value range includes the value of the data point.

    Every PLOT command requires one qualifier from the data kind and
    the sorting categories to generate a histogram. If you do not
    specify one qualifier from each category, a default qualifier is
    used. If your PLOT command has one or more node specifications,
    the qualifier defaults are taken from the SET PLOT defaults.
    If your PLOT command does not have a node specification, all
    qualifier and node specification defaults are taken from the
    previous PLOT or TABULATE command you entered.

    The TABULATE command displays the same information as the PLOT
    command, but in the form of tables instead of histograms.