how could I figure out how many gmails were sent at the specific period?

I would like to know how many email were sent from my account during certain period. How can I know that? The reason why I have to figure out it is that I need to prove the # of email I sent during that period. The accused claims that I deleted emails which is important for the case. I have to prove I didn't deleted any email during that period. I requested the data analysis to Gmail, google but they didn't answer anything right now. Please let me know any possible method that I can prove. Thanks.