This report gives you a break down of the current values of one or more fields in a set of issues. The field you select for the Value Of option will be shown as individual values on the range (Y) axis. The quantity of issues that have the specified field value will be shown, and the horizontal bars will be broken down by any of the segmentations that you have specified in the Segment By option.
Run a Current Issue Values Report and specify Status for the Value Of option to get a snapshot of the current status of issues in one or more projects. To break down the results to identify users with the largest number of issues assigned to them, select Assignee for the Segment By option. If you want your report to show only a subset of issue statuses, you can change the search filter to include only the statuses you want. For example, in the JQL option, you could specify 'project=MYPROJECT and status in ("open","in progress")'.