Max function between dates
 

Have a spreadsheet, Column A is every day ( dates, Jan 01,
2003, Jan 02, 2003 ect.... ) Column B is how many emails
where sent that day. Im trying to automate a function

Max( # of emails sent in last 30 days, 60 days ect.. )
The table is updated weekly and trying to make it
completly automated so i dont need to switch the formulas
every week

Can anyone help me, if any additional info is needed post
questions

Thanks in advance !

Jay