Retroactively run weekly reports to graph trends

Hi,

I am hoping someone can help me out - I am not sure if I am running into a limitation of the program, or a limitation on my understanding of how to create a custom report...

I am trying to run a report which can show the total number of pending requests in a given week along with the number of requests added during that week.

In the same report I would like to show the number of both closed or resolved requests for each week.

I want to be able to retroactively go back say 6 months or a year to show the trends and be able to graph the flow of requests inbound and outbound.

My end goal is to be able to demonstrate if there is a need for additional help in our department.

Regards,
Chris Davis