Hello Brooke!
We do not remove any of those records, we also do not place a limit on how many of those records you may have or a cut off date for tracking that information. However, CRM may place a restriction on the amount of records you can have in a view but you are able to disable record limits for on-premise CRM, as outlined in this article: http://blog.dorrekens.com/index.php/list/79-changing-the-5000-record-count-limit-in-crm-2011
This is a potentially risky modification and, while I am passing along the information I found, it is not something that we can directly support. I would run this by your CRM Administrator before making any changes.