The Date Histogram function can help you quickly identify if you are missing documents in a particular date range as well as give you a sense for volume of information by time.
To use the Date Histogram:
1.You will need to perform a search in Review first. The Date Histogram tool operates on the results that are returned from that search.
2.From the Analysis menu, select Show Date Histogram.
3.Use the Years and Months options to change the display.
4.Clicking the Save Chart… button will allow you to save the current chart as an image file.