How MR DB size is increasing without running reports in AX 2012 R3?

Hi All,

        I installed MR in AOS server and configured MR by using  configuration console.

My AOS is in one server and Databases are in DB server as follows.

AOS server:

Windows Server  : Windows 2012 R2  

AOS                      : AX 2012 R3

Management Reporter : MR 2012 CU12

DB Server :

windows Server      : Windows 2008R2

SQL Version             : SQL 2012 SP1 Enterprise Edition (64-bit)

MR DB Name          : ManagementReporter_23test

DataMart DB           : ManagementReporterDM_23Test

AOS DB                    : MicrosoftDynamicsAx_23

integration is successful and both services are running,Mr is working fine.

now my worry is Both MR DB and Data Mart DB sizes are growing rapidly without running any reports.

22-11-2015 both DB's are around 8 GB in size

24-11-2015 both DB's are around 21 GB in size.

Kindly help to find out how this DB size is increasing everyday,and where can i find this,how to control .

Thanks & Regards

Naresh.D