Are you using Info records to record your leads?
This is a great recording feature within Mercury.
If there are specific people with your company who deal with Business Development, and all leads go to those people, ensure that when you create the Info record, update the Owner field from your name to the person you wish to assign the Info to. They will not be sent a notification but when they review their list of Info records, it will show your name in the Created By field:
For reporting purposes, there is the option to report on the number of new Info records created by each user and to report on the number of converted/lost Info's over a set period, by the Owner of the record.
These look great when reported within a chart, to see the number counts.
Take a look at how to create charts within Mercury Assist.