Reporting on the values of custom numeric ticket fields for a certain date

Hi,

We have custom numeric ticket field "Counter" that is updated with +1 each time an agent makes a contact with the customer. 

1. How can I create a report that will show me the exact value the custom numeric field Counter had for a certain date?
2. Additionally I would like to see how many times the value of this specific custom numeric field was changed for a specific period of time? For example if the agent has updated a ticket 10 times in June, but only 3 of those updates included a change in the value for field Counter, the report should show 3.

Thank you in advance for the help!