DDL_Events record life span

For how long are records retained in the DDL_Events table ?
I have 2 installs that have been active for over a year and all records prior to 12/2015 are gone. Why is that ?
I have 2 installs that have been active for over a year and all records prior to 12/2015 are gone. Why is that ?
Comments
Stored Proc RG_SQLLighthous_WriteEvent << That's a Bad IDea, in my opinion.