Use the admin area, apps, or the REST API to obtain counts in each statistic area below. Pay particular attention to your largest object counts and database tables. Make a prediction for what type of growth or decrease to expect. Include any additional information or factors influencing the data. Include instructions to easily get to the data again (a URL, sample query, etc.) Link any Jira items created in response to a prediction. E.g., Increase limits on attachment storage space.
Repeat this effort quarterly or semi-annually, as needed for your growth rate.