The Assignee Count data shows how many times an issue has been assigned to a particular assignee during a chosen period. So you can monitor how many times an issue has moved from one team member to another (and vice versa) easily.
For example, if you need to know how the number issue has moved to somebody during a Sprint period, you need to:
Choose the Time in Status report. Filter by the Sprint and choose the sprint you need.
2. Switch to the Pivots.
3.Click the Fields option.
4. Move the chosen fields to the appropriate column as it’s shown below:
Priority → Report Filters
Key → Rows
Assignee → Columns
Choose Count of Time (hours) from the drop-down list in the Values column.
So, you’ll get such grid with how many times an issue has moved to a particular assignee: