There are several types of histograms here:
The histogram is of cpu time as recorded by Condor
The histogram is of wall_clock time as recorded by Condor
The histogram is of time spent copying files in from jobs
The histogram is of time spent copying files out from jobs
This page prints a horizontal histogram of times related to jobs in the campaign.
Bars on the histogram are labelled with the exact count, and the bars are links to a table of jobs counted in that bar.